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620slodat

1979 620 fuse block and wiper motor

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To start with I've spent several hours searching and can't find what I need.

 

I recently purchased a 1979 620 King Cab for parts. It appears that the pickup was equipped with at least the delayed wipers (I found the delay set up, and it seems to work), a 5 speed transmission, and maybe more. The following are the first set of questions I have. There will most likely be more to come as I may not get all the information needed between the wiring diagram and my searching.

 

1 & 2--There is no cover over the fuse block, and I need to know what size fuses are needed, and what each fuse goes to. A pic would be ideal if you have a cover over your fuse block. The fuse block in there has one flat edge and one edge with a semi-circle for part of it. I have 12.6+ volts up to the fuse block, but only about 10.5 volts at the wiper motor. Is this enough?

3--Is there a relay in between the fuse block and the motor? I can't find any on the wiring diagram, and searching under the dash is very time consuming, and hard. 

4--The motor appears to work when I test it out of the vehicle, but the motor will not park. If anybody has experience with the wiper motor testing I want to hear it.

5--Will the park function work properly if the motor is rotated where it mounts to the firewall, but the wiper arms are put back on compensating for the different park position? I think it will, but have no experience with doing this.

 

Don

Edited by 620slodat

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Delay wipers were only available on the '79 King Cabs.

 

Five speeds were only ever an option on '77 and up trucks

 

 

1/ Fuses:

Front left 10 right 10

Middle left 15, right 15

Rear left 10 right 15

 

2/ low 10.5 volts... clean fuse clips. Should still turn but 12v would be faster.

 

3/ A relay? for the wiper?? No, power from the ignition goes through the fuse box to the wiper motor. It's on all the time the ignition is on. The wiper switch selects a ground in the two pull out positions to turn the wipers on. When the wiper switch is turned to off, it connects the park circuit. This is an internal set of points set to open at the park position and turn the motor off. 

 

4/ If you have the wiper motor out put ...

 

12v on the Blue/Red strip wire

Ground the Black wire.

 

a/ If you jumper a ground to the Blue wire you should have low speed.

b/ If you jumper a ground to the Blue/White wire you should have high speed.

 

c/ Jumper the Yellow and Blue wires together and this activates the park circuit. If already parked nothing will happen.

 

 

If you can get  a / b/ c/ to work but it doesn't work in the truck then the wiper switch is maybe faulty. Or bad connection.

 

 

 

 

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Thank you DM!! I've made some time and started doing some checking, and so far I have high and low speeds, but I haven't found any park function yet. To get the park function you say to jumper the blue and yellow wires. Are you talking about connecting the blue and yellow in the switch? My wiper motor does not have a yellow wire. There is a yellow wire in the wire loom from the switch. But, it dead ends in the connection block at the wiper motor. I only have four wires on the wiper motor side of the connection block.  Red (12V+, connects to blue/red stripe in the loom), White/Blue stripe (connects to blue/white stripe), Blue (connects to blue), empty spot (connects to yellow in the loom), Black (ground, connects to black). I haven't had time yet to look at the wiring diagram.

 

Don

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I just now took some time to look at the wiring diagram. The diagram shows a yellow wire on the wiper motor, but I don't remember any evidence of a yellow wire on the wiper motor. It's dark outside now and I put the wiper motor back in the pickup, so I will have to look at the wiper motor some other time. I don't think I will have any time to look tomorrow.

 

Don

Edited by 620slodat

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1 hour ago, 620slodat said:

  To get the park function you say to jumper the blue and yellow wires. Are you talking about connecting the blue and yellow in the switch? My wiper motor does not have a yellow wire. There is a yellow wire in the wire loom from the switch. But, it dead ends in the connection block at the wiper motor. I only have four wires on the wiper motor side of the connection block.  Red (12V+, connects to blue/red stripe in the loom), White/Blue stripe (connects to blue/white stripe), Blue (connects to blue), empty spot (connects to yellow in the loom), Black (ground, connects to black). I haven't had time yet to look at the wiring diagram.

 

Don

 

23 hours ago, datzenmike said:

 

4/ If you have the wiper motor out put ...

 

12v on the Blue/Red strip wire

Ground the Black wire.

 

a/ If you jumper a ground to the Blue wire you should have low speed.

b/ If you jumper a ground to the Blue/White wire you should have high speed.

 

c/ Jumper the Yellow and Blue wires together and this activates the park circuit. If already parked nothing will happen.

 

 

If you can get  a / b/ c/ to work but it doesn't work in the truck then the wiper switch is maybe faulty. Or bad connection.

 

 

 

 

 

I looked and if you have the delay wipers (or not) the wiper motor and connector has 5 wires and one connects to the Yellow wire in the harness.

 

What are the color of the wires on the motor side. Again there should be 5 and one (may not even be Yellow) must connect to the Yellow in the harness.

 

 

Basically all the delay does is turn the wiper on for maybe a second and then shut off. Same as if you pulled the wiper switch on and then shut it off. The wiper motor will continue running in park mode and stop. After a sew seconds the delay amplifier sends another pulse to start the wiper motor again

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On 10/23/2020 at 7:09 PM, 620slodat said:

 But, it dead ends in the connection block at the wiper motor. I only have four wires on the wiper motor side of the connection block.  Red (12V+, connects to blue/red stripe in the loom), White/Blue stripe (connects to blue/white stripe), Blue (connects to blue), empty spot (connects to yellow in the loom), Black (ground, connects to black).

 

Don

 

I got the wiper motor back out of the pickup, took the cover off the transmission portion of the motor and did a continuity check. The plastic connector is riveted to the wiper motor transmission cover. Both the blue wire and the metal connector for the yellow wire (for the park function from the loom/switch) go through the plastic connector block using two copper springy strips on the inside of the transmission cover carrying the park function into the inside of the transmission cover, without using any visible wires to carry the park function into the motor. That is why I didn't see the yellow wire from the loom going anywhere beyond the connector. There were only four visible wires, not five.

 

The copper springy strips that go inside the transmission cover touch against a short metal plate on the side of the nylon gear. This short metal plate only goes a small way around the gear, but this short metal plate is wide enough to connect the two wires together and exciting the park function. The metal strip (closest to the center of the nylon gear) that connects to the yellow negative park function wire (from the loom) also runs against a longer metal plate. This longer plate goes all the way around the nylon gear, except for where the short metal plate is and about 3/16ths on either side of the short metal plate. This longer metal plate keeps the yellow wire in contact long enough for the park function to work when it is called for by the switch.

 

I know this is confusing, and a picture is needed. I tried to put a picture on here, unsuccessfully. My daughter has been gone all day, and when she gets home later this evening I will get her help.

 

Don

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I can follow because I had my 620 wiper apart and with a diagram I worked it out.

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DM, I appreciate you and your abilities. I'm glad that you were able to understand my ramblings. But, because you are not the only one reading this thread I'm still planning to get some help to post a picture of the inside of the wiper transmission.

1 hour ago, 620slodat said:

 

I got the wiper motor back out of the pickup, took the cover off the transmission portion of the motor and did a continuity check. The plastic connector is riveted to the wiper motor transmission cover. Both the blue wire and the metal connector for the yellow wire (for the park function from the loom/switch) go through the plastic connector block using two copper springy strips on the inside of the transmission cover carrying the park function into the inside of the transmission cover, without using any visible wires to carry the park function into the motor. That is why I didn't see the yellow wire from the loom going anywhere beyond the connector. There were only four visible wires, not five.

 

The copper springy strips that go inside the transmission cover touch against a short metal plate on the side of the nylon gear. This short metal plate only goes a small way around the gear, but this short metal plate is wide enough to connect the two wires together and exciting the park function. The metal strip (closest to the center of the nylon gear) that connects to the yellow negative park function wire (from the loom) also runs against a longer metal plate. This longer plate goes all the way around the nylon gear, except for where the short metal plate is and about 3/16ths on either side of the short metal plate. This longer metal plate keeps the yellow wire in contact long enough for the park function to work when it is called for by the switch.

 

I know this is confusing, and a picture is needed. I tried to put a picture on here, unsuccessfully. My daughter has been gone all day, and when she gets home later this evening I will get her help.

 

Don

 

KIMG0636.JPG

Edited by 620slodat

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7 minutes ago, 620slodat said:

DM, I appreciate you and your abilities. I'm glad that you were able to understand my ramblings. But, because you are not the only one reading this thread I'm still planning to get some help to post a picture of the inside of the wiper transmission. 

 

KIMG0636.JPG

 

My daughter was here and had to leave again, so I got my son's help. I don't know what he did, but in just a few clicks he had the picture uploaded (he is poor at explaining in simple enough terms for me to understand). He had it done so fast that I didn't even get to finish a post I had started. So, another post here we come. This is a pic of the internals of a wiper motor transmission for a Datsun 620.

 

If you don't know what a wiper motor transmission looked like, now you do. If you put this picture together with my ramblings you might be able to understand what I'm trying to say. If anybody has questions I will try to explain.

 

Since I got low and high speeds to work, and I get continuity for the park function, the switch is probably needing to be cleaned up to get the park function to work properly. I will check that out next. It may take me a few days to find time to check out the switch. We are having clear blue skies when it is usually raining and wet. So, "I have to make hay while the sun shines". In other words, I have lots to do around the place that is best done when it is dry.

 

Don

 

1 hour ago, 620slodat said:

 

I got the wiper motor back out of the pickup, took the cover off the transmission portion of the motor and did a continuity check. The plastic connector is riveted to the wiper motor transmission cover. Both the blue wire and the metal connector for the yellow wire (for the park function from the loom/switch) go through the plastic connector block using two copper springy strips on the inside of the transmission cover carrying the park function into the inside of the transmission cover, without using any visible wires to carry the park function into the motor. That is why I didn't see the yellow wire from the loom going anywhere beyond the connector. There were only four visible wires, not five.

 

The copper springy strips that go inside the transmission cover touch against a short metal plate on the side of the nylon gear. This short metal plate only goes a small way around the gear, but this short metal plate is wide enough to connect the two wires together and exciting the park function. The metal strip (closest to the center of the nylon gear) that connects to the yellow negative park function wire (from the loom) also runs against a longer metal plate. This longer plate goes all the way around the nylon gear, except for where the short metal plate is and about 3/16ths on either side of the short metal plate. This longer metal plate keeps the yellow wire in contact long enough for the park function to work when it is called for by the switch.

 

I know this is confusing, and a picture is needed. I tried to put a picture on here, unsuccessfully. My daughter has been gone all day, and when she gets home later this evening I will get her help.

 

Don

 

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Since this thread has ended up including the wiper motor, I added wiper motor to the title.

 

I made a little bit of time to do some checking on the wiper motor today. I used my Astro van as the power source and did some checking of the wiper motor. I got low and high speeds, but still never got the park function to work. I kept the power (12V+) and the ground (12v-) hooked up and tried several ways to get the park function to work. But no success with getting the park function working. The output shaft stopped any place it wanted when the power to the low speed was removed. I may be doing things all wrong, so I need someone to go over again what is needed to make the park function work. In all my checking I kept the power (12V+) and the negative (12V-) hooked up since that is what I though the pickup would do. I bridged blue and yellow, no park function. I bridged blue, yellow, and low speed, no park function. Can anybody help me out with ideas?

 

Don

Edited by 620slodat

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KIMG0636.thumb.JPG.ffd9176cdd4e0ed1dbfe4

 

Did you clean these two contacts? and make sure they touch? They look a little burned???? Perhaps the blades were frozen to the glass when the wipers were turned on and couldn't park. Things would get hot. The fuse would blow to protect the wiring but the park contacts may be damaged.

 

Find a way to join those two wires. (Red and Blue???) Try the harness and the motor side of the plug (this eliminated the plug as the problem, both sides should work).... and the wipers should not shut off with the switch.  If you can get that to work, then the only thing left are those contacts.

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The wiper motor was out of the pickup when I checked function a second time, yesterday. I used the wire colors to check high and low speeds, and they were there. Although it doesn't show there, I used some fine emery cloth to get the tips of the contacts bright. I never thought about the contacts showing that they might have been hot at some time, but I will check it. I didn't actually check for contact with the metal plates. Looking back I'm sure that contact was made, but I'll double check the contact this evening. I tried joining the two wires on the harness side, but I didn't get any park function. I will see what I can do about getting the park function from the motor side tomorrow.

 

Don

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KIMG0636.thumb.JPG.ffd9176cdd4e0ed1dbfe4

 

If the red and blue wires in the picture go to the two contacts, follow them back to the plug. Install wiper, plug it in and find a way to jumper these two wires on the harness side. Turn key and wiper on and it should park when tuned off.

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I was wrong. The contact points inside the transmission were not touching the metal plates. Also, the points may have been burnt. When I tried bending the contacts back into touching the metal plates the contact strips were not as "springy" as I thought they should be. Because of the softness of the metal strips I will see if I can find another wiper motor. I am concerned about future loss of contact with the metal plates. Because it is still dark here I will have to wait until later to try the wiper motor park function. But, I will try again.

 

Don

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I currently have the wiper motor working, with the park function (I think). My question now pertains to voltage. I get 12.4V+ at the battery I'm using, 12.4V+ at the ignition switch, 12.4V+ at the fuse block, but only 10.5V+ at the wiring connector at the wiper motor. According to what I'm seeing on the diagram there are two wiring splices between the fuse block and the wiper motor, but no connectors. What I'm wondering is for those of you who have experience with this circuit, is this correct? Without going under the dash (and spending a lot of time) I'm wondering what there could be between the fuse block and the wiper motor to reduce the voltage. 

 

Don

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What about the fuse box end of the wire that has 10.5v??? Yellow/Red stripe wire. This fuse powers several other things as well, like the heater fan and the washer motor, not just the wiper 

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I checked both ends of the fuse, 12.4V+. I also pulled all the fuses and put one at a time into the fuse block until power went to the wire to the wiper motor. But, like DM said, power may not go all the way through. I need to check the brass part that holds the fuse. That is why I like this site. Somebody will say something that will bring to light something else to check. Thanks DM!

 

Don

 

 

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Try the heater motor see if it's 10v.

 

My guess is the fuse box clips or maybe the fuse if you haven't changed it. I had a bad (corroded?) fuse clip in my 620 and the lights would sometimes shut off. You reach down quickly and push on the fuse and they come on. The last time I burned and blistered my finger. The only possible fix was to replace the fuse box because the clips had been so hot in the past they were soft and had no grip on the fuse... a vicious circle. 

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I'm going to need another fuse block. The back left hand fuse was loose from the beginning several days ago. A couple days ago I tried gently squeezing the clips together and the clip broke. When I looked at the break area It was easy to see that the metal had been already fatigued and was very very thin at the break. Consequently, with the low voltage for the wiper motor I decided yesterday to get a new fuse block. I haven't decided yet what to get, but I'm leaning towards getting a brand new block, probably a blade type. I will need to spend some time. Then I will trouble shoot the voltage problem, if needed with the new block.

 

I'm open to suggestions for a new fuse block. 

 

Don  

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There's only 6 fuses so it should be simple. The next truck the 720 has 15

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On 11/3/2020 at 12:26 PM, datzenmike said:

Try the heater motor see if it's 10v.

 

My guess is the fuse box clips or maybe the fuse if you haven't changed it. I had a bad (corroded?) fuse clip in my 620 and the lights would sometimes shut off. You reach down quickly and push on the fuse and they come on. The last time I burned and blistered my finger. The only possible fix was to replace the fuse box because the clips had been so hot in the past they were soft and had no grip on the fuse... a vicious circle. 

 

Before they closed you could buy individual clip blocks [for fuses and solid state diode packs] from Radio Shack.  You could disassemble the clips and retrofit fuse block arrays..  Maybe there is some real electronic parts store or catalog remaining ?

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I checked for Radio Shack on-line, but nothing about who took over was in this area close to me.

 

Since It was raining this afternoon I used that excuse to spend the afternoon looking on-line at fuse blocks, mostly the blade type. I liked the quality of Blue Sea, but the price! I like the blocks that have a small LED that lights up when the fuse blows, but Blue Sea didn't have that that I could find. But, that probably adds something that will break down. Does anybody have this feature that can tell me if it is any good?

 

What I was looking for was a split system, part will work without the key on, and part will need the key to be on and powered. Most that I found on-line was at least 12 circuits (6 and 6), and I don't think I will need that many circuits, even with adding a few. I don't need the negative strip that most Blue Sea blocks had. My negative system goes through the frame/body, as do all the Datsuns that I'm familiar with. I DO want a clear cover over the block. I may need to get two separate blocks to get the split system without having a large quantity of fuses. I need to go to town tomorrow to get some special chicken feed that I ordered, so I'm going to have to check and see what is available locally. I will also pull the currant fuse block to see if anything close in size can be found.

 

Don

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Hey Don! I've been meaning to call you now that I'm mobile again.  There is a small box of parts, some of the fixed window trim pieces and the factory jack... other small stuff can't remember. It's at Laurel's where I'm still working on stuff. I have a couple of nice 620 fuse blocks with the plug, and one with out, in my storage unit. There might be a cover too, but not in great shape. I also have the variable speed switch and both plugs, with the nuts, washer and plastic bushing for dash mount... I just came across in a box of 620 junk. You are welcome to anything you can use...

 

Things are still a little sideways, but I would be up for a trip to drop stuff off. I will try to remember to call you...

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Thank you for the offer! I have pulled the instrument cluster out as of yesterday (a whole story in itself). The tach was wired in with a scotch lock and a wire nut. One of these two was just barely long enough to get the cluster out just a little ways. The third wire is stretched out through the dash cavity. How it is hooked up is yet to be found out. I haven't looked very close at the wiring yet, but seems to be OK. The tach and radio are not stock with this vehicle. This was all done to figure out the fuse block. The wiper fuse is still intact, and the scotch lock was on that wire, between the fuse and the wiper motor. I had only 10.5 volts at the wiper motor, and 12.3+ elsewhere. I carefully squeezed the fuse clamps together, and one was just barely held together and broke. All the rest seemed to hold together alright (haven't cleaned them yet). The short story is that I either need a different fuse block, or a new fuse panel. I do have a blade style fuse panel, but it is not wired in yet. The quickest thing would be to repair the original fuse block. I will take a look at it and see if the clip can be replaced. If so that would be the quickest way to get it going again. 

 

I have been planning to go up to see wayno and get a ride in his pickup with the stock rear leafs to find out what the stock 720 rear suspension is like. The rain is here most of the time, and outside chores are almost out of the question now because of the rain ( i had to work rain or shine growing up and I am now against working in the rain). So, consequently I have been thinking very much about seeing when he is available. If so, I would be going past there on I-5. I don't know yet when though. I will keep in touch. 

 

Don

ps-I need your phone number so I can put it into my cell phone. I have looked for it, but so far no luck. I have been getting a LOT of scam calls lately and have been ignoring any calls that don't have a number/name in my phone. PM me with it so it won't be on the internet.

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