Fusible link blown.

[Guest jaimesix]

Hi.

 

I have a question, hope the gurus can give me a hint.

As I drove my 710 last time, I noticed the charging light on.

I decided to stop using the car to check the alternator and Volt reg that I had changed about 9 mos ago. As I checked the relay area in the engine bay I noticed the fusible link cable burnt. The fusible link arrangement has a cable connected to the battery on one side. On the other side it is connected to the engine wire harness via 6 connector plug male/female.

 

The plug/connector from the fusible link assembly ( male component of connector to wire harness ) and the female side of connector attached to wire harness had one connection overheated, to the point that the female side was melted on that particular point ( one of the 6 points within the conector.)

 

I took my alternator to the shop where I bought it ( Rotex , in Gardena.) and after testing it,they told me the Alt was fine. They could not check the voltage regulator because they did not have the layout of said Volt Reg. 9 mos ago I changed both units, alt and volt reg.

 

I am going to reconnect the cables and replace the fusible link. My Datsun 710 books have wire layouts for 76 and 77 year models. Mine seems to be different, the cable colors do not match the books layouts. One WR ( white red.) One GY ( green yellow ) One R ( red ) and one that seems to be brown, light brown. That is the one that overheated.

 

Since my books diagrams do not match my cars' wire colors, I can not trace it.

 

I am not doing anything to the car right now. I need to think. Any suggestions?

 

Jaime._____________________________________________________

[fiveNdime]

I would first start with hooking it all back up. Bypass the Fusible link and check the voltage coming into the battery when running. You should be able to see if its overcharging which is what it sounds like. The regulator could still be bad even if its a day old....I had one bad right out of the box. The alt is probably good if they tested it.

[Guest jaimesix]

I would first start with hooking it all back up. Bypass the Fusible link and check the voltage coming into the battery when running. You should be able to see if its overcharging which is what it sounds like. The regulator could still be bad even if its a day old....I had one bad right out of the box. The alt is probably good if they tested it.

 

Thanks.

I will have that regulator checked before proceeding. If I can assume both parts are fine, that will make it easier.

 

I am going to look for another Volt Reg anyways, good to have a spare. I am hoping it is the Voltage Regulator. If not, there must be a short somewhere....but I will find it.....

I will get pixes of the burnt cables.

 

Jaime.__________________________________________________-

[Guest jaimesix]

Pictures. Here you can see my fusible link assembly and another found at the junk yard that I will use for replacement ( Thanks William.)

 

You can see the burnt plastic, cable and connector, as well as the wire colors ( different from any Datsun 710 lay out I have read about.)

 

[zerow]

All right - I thought the part would work. :mellow: Do you need to borrow the voltage regulator from the parts car?? As well as the fusible link?? Both are in working order, you just owe me if you blow them up. :D I will be in the area on Saturday morning, PM me for more info, and I can have the parts out of the car and with me for the trip.

 

-0-

[Guest jaimesix]

All right - I thought the part would work. :mellow: Do you need to borrow the voltage regulator from the parts car?? As well as the fusible link?? Both are in working order, you just owe me if you blow them up. :D I will be in the area on Saturday morning, PM me for more info, and I can have the parts out of the car and with me for the trip.

 

-0-

 

Thanks William. I will let you know. I need to find out if this Voltage Regulator is bad, if not, there is some other short in the car's system. If the Volt Reg indeed is broken, that takes away the headache.

 

Jaime._______________________________________________________

[hang_510]

not on a 710, but the only time i melted the fusible link connector was due to a bad alt (not your issue) which was also related to poor grounds.

check those too!

[Guest jaimesix]

not on a 710, but the only time i melted the fusible link connector was due to a bad alt (not your issue) which was also related to poor grounds.

check those too!

Yes, good point. I will check the ground strap and alt ground as well as batt ground.

Thanks.

 

Jaime.______________________________________________________

[Guest jaimesix]

I never finished this thread, but since cool Bonvo is having trouble with his charging system, I will give a final explanation of what transpired.

 

Thorough inspection of the car electrical components of the charging system left the following impression:

 

1) The fusible link was definitely gone.I replaced it with a used one from a junk yard car. Thanks to "Zerow", he got it for me. Zerow, you are "Da Man".

2) Alternator was in good shape, took it to the shop were I got it ( life warranty. cool guys ) and inspection determined it was in perfect shape.

3) My theory is that the fusible link blew because something shorted out, and in the process, the VR blew up. Detailed inspection of wiring showed that the cables connecting to the starter were chaffed by means of rubbing against the starter body/ selenoid itself.

Also, a section of the engine compartment harness runing down on the battery side of the frame, across from the starter, over the unibody's boxed frame member was chaffed and rubbing freely against body of box frame section.

I used regular rubber hose ( like gasoline rubber hose or water hose ) to cover, protect and isolate said cables.

After doing this, I tried the car by turning the ignition switch on ( batt already charged with my Pep Boys batt charger.). The Charge light was still turning on. That indicated that the voltage reg was the next bad link to work on. Alternator taken out from the problem list, as well as chaffed wires , left the VR as the next suspect to be intervened!

4) I had no way of checking the Voltage Regulator, so I just bypassed that imposible test and bought a new ( e/bay) VR. By logic, if the VR is bad, a new VR will allow the system to work fine. The Alternator is fine, no more wire chaffed issues , so the only bad part could be the VR.

5) New VR installed, turned the Ign switch on, and voila! no more charging light boogies.

 

:cool:

[bonvo]

thanks alot jaime for the info i think my new h4 lights were drawing to much power thats the only thing that could have killed it i was already running an electric fan befor and had no issues the only thing elecrticalwise that has changed was then lights the strange part is this my charge light never came on:confused: so im thinking the vr might still be good we will see after i replace the problem wires

[74datsun]

Hi.

 

I have a question, hope the gurus can give me a hint.

As I drove my 710 last time, I noticed the charging light on.

I decided to stop using the car to check the alternator and Volt reg that I had changed about 9 mos ago. As I checked the relay area in the engine bay I noticed the fusible link cable burnt. The fusible link arrangement has a cable connected to the battery on one side. On the other side it is connected to the engine wire harness via 6 connector plug male/female.

 

 

 

Where is the Voltage regulator on your 710??? If you could help out that would be most excellent.

[datzenmike]

The engine harness is between the outer and inner fenders and enters the engine compartment behind the black plastic box shown. Headlight and choke heater relays, voltage regulator and fusible links are on a metal chassis mounted to the inner fender and covered by the plastic box.

 

'74 710

 

 

'75 and later 710

 

 

Behind the black plastic box is a metal chassis with everything mounted on it. You have to loosen it and tilt it toward the engine to get in behind where the voltage regulator is.

 

 

 

 

.

[banzai510(hainz)]

Neihoff usa made VR suck. They dont last as long and I had overvolt issues with them.

 

find a solid state units dont matter who makes it but solid state is better

ck rockauto.com the SS unites will have a smaller can size