laotsu Posted January 26, 2011 Report Share Posted January 26, 2011 SO... (deep breath) I had a charging problem and was dumb enough to replace the alt and volt reg before I realized that all that was wrong was a corroded fuse that looked good. Nothing like $75 in parts to realize I needed a ten cent fuse. car runs and charges fine now, my turn signal dont fuck up like they used to. BUT JESUSTITTYFUCKINGSANTACLAUS! The damn headlights aint working now, but the running lights come on. I replaced all the fuses so I dont think its that. since the running lights come on Im pretty sure the switch is working. the lights were fine before all this bullshit so Im pretty sure the bulbs are ok but Im not sure how to check em. how do I find the problem? god I feel like a loser :poke: 1 Quote Link to comment
skunk Posted January 26, 2011 Report Share Posted January 26, 2011 did you clean your fuse box after taking out the corroded fuse? Quote Link to comment
MicroMachinery Posted January 26, 2011 Report Share Posted January 26, 2011 Jiggle the connectors at the lights, and the headlight switch. Sounds like you've got some corrosion issues, so it could just be that there's a dirty connection somewhere. Always check all the simple stuff before you start guessing and throwing money at it. Quote Link to comment
banzai510(hainz) Posted January 26, 2011 Report Share Posted January 26, 2011 get a test light. ground one end with light switch in the OFF position use the pointy end and and ck all 3 connections at back of lamp(you dont evn need to remove the connector). If it lights up then your getting power from the battery to the fuse box to the lamp. then most likey a ground proplem at the relay. wiggle that connector. depending on year soem fuse boxes have a red/yellow stripe wires I think and theres a connection up buy the fuse box. ck there also. I assume you put new lamp fuses in also just in case. I really never heard of a fuse fixing a charging proplem as the alternator feed wire is shorted battery,maybe I guess thru the volt reg via the key switch (ignitionfuse) Quote Link to comment
Skib Posted January 26, 2011 Report Share Posted January 26, 2011 I realized that all that was wrong was a corroded fuse that looked good. replace all the fuses and soak your fuse block in vinegar. 1 Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 yeah I forgot to mention its a 71 pl521 and the fuse diagram is gone and I cant find one online so I just replaced all the fuses with the same amperage Quote Link to comment
Skib Posted January 26, 2011 Report Share Posted January 26, 2011 yeah I forgot to mention its a 71 pl521 and the fuse diagram is gone and I cant find one online so I just replaced all the fuses with the same amperage duuuude...... :blink: not a great idea. good way to start frying wires Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 noooo I mean teh same amps a s b4 Quote Link to comment
Skib Posted January 26, 2011 Report Share Posted January 26, 2011 noooo I mean teh same amps a s b4 ok, whew.... I thought you went and put the sam amp fuse in all of them :o carry on. :cool: Quote Link to comment
banzai510(hainz) Posted January 26, 2011 Report Share Posted January 26, 2011 ok this is a 521 dont go by my above instruction as I dont think 521s are switchble ground lighting. I had this happen before. make sure the wires are connected good. 521s have lots of corrostion there. use the correct fuse ampreage. do your HIGHbeams work? Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 no headlights at all Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 think Im gonna clean the fuse block, but the running lights make me think the lamps are getting power Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 but the running lights... Quote Link to comment
banzai510(hainz) Posted January 26, 2011 Report Share Posted January 26, 2011 dont think like that. Running lights is running lights. not headlamps. there might be a white wire by the battery to fuse box ck this. its important but ai cant remember for what Quote Link to comment
Skib Posted January 26, 2011 Report Share Posted January 26, 2011 think Im gonna clean the fuse block, but the running lights make me think the lamps are getting power go grab your test light, turn the headlights on and stick it in the headlight plug and find out. Quote Link to comment
laotsu Posted January 26, 2011 Author Report Share Posted January 26, 2011 go grab your test light, turn the headlights on and stick it in the headlight plug and find out. Ima gonna use a multimeter... OK? Quote Link to comment
Skib Posted January 26, 2011 Report Share Posted January 26, 2011 thats fine, cuz your either getting voltage to it or your not. Quote Link to comment
banzai510(hainz) Posted January 26, 2011 Report Share Posted January 26, 2011 i think its corrossion by the fuse box area to or from it I had this happen twice on my 521 Quote Link to comment
DanielC Posted January 26, 2011 Report Share Posted January 26, 2011 521 use a switchable hot side of the headlights. If the truck is stock, the second fuse in from the center is the headlight fuse. Power comes from the battery positive post, to this fuse. After the fuse, it goes into the cab, on a thick red wire. There is a connector behind, and above the glovebox. The thick red wire goes through this connector to the light switch. There are two separate switches in the light switch, the headlight is independent of the tail, marker, and instrument lights. The headlight switched power is on a thick red wire, with a yellow stripe. It goes back to the connectors behind the glovebox. The red, with yellow wire goes to the headlight relay mounted on the fender, by the battery. The relay normally connects the red, with yellow wire to the red with black wire, and that wire goes to the two low beam headlights. Inside the relay, the power is applied to the relay coil anytime the headlights are on, but the relay coil is not grounded. When you switch the dimmer switch on the steering column, it grounds the relay coil, with a green wire, with a white stripe. I am not really sure on the color of this wire, but it is the only thin wire on the headlight relay. With the relay coil grounded, it switches the power coming onto the relay on the red with yellow wire, from the red with black wire, to the red with white wire, and this turns on the four high beam headlights. The headlights on a 521 are grounded by a black wire, that goes back to a lug under one of the voltage regulator screws. There is also a second black wire grounded here, and that goes back to the frame of the alternator. The frame alternator ground also has a black wire that goes up to the lifting lug, by the fuel pump, and that goes back to the battery, negative terminal. Quick tests. Turn the headlight on, or at least pull the switch all the way out. Check for power on both sides of the fuse. Check for power on the fuse box lug the red wire is attached to. If power there, check for power on the red with yellow wire attached to the headlight relay. Check for power on the red with black, and red with white wire on the relay. Check for power at the headlights. That should get you started. Quote Link to comment
elmerfudpucker Posted January 27, 2011 Report Share Posted January 27, 2011 Did you clean your headlight switch? My 720 did the same thing, cleaned the switch with Q-tips and vinager. Quote Link to comment
wayno Posted January 27, 2011 Report Share Posted January 27, 2011 The headlights quit working when he messed with the fuse block, I would concentrate there first, it's 40 years old. That is my headlight issue, wiggle the wires and presto, headlights. Mine is also a 71 pl521. wayno Quote Link to comment
DanielC Posted January 27, 2011 Report Share Posted January 27, 2011 Here is a really nice picture of the 521 fusebox, I swiped from another forum post. Thanks. The red wire, second in is the wire that takes the power from the fusebox, to the headlight switch. It is the one with the slightly burnt boot covering the spade connector. Here is a picture of the relay connections. Swiped from the same forum post. The red wire, with the yellow stripe should have power on it when the headlight switch is on. The red with white goes to the high beam headlights. The red with black goes to the low beam headlights. The green wire with the yellow stripe goes to the dimmer switch, and is grounded by it. Quote Link to comment
laotsu Posted January 27, 2011 Author Report Share Posted January 27, 2011 Here is a really nice picture of the 521 fusebox, I swiped from another forum post. Thanks. http://i258.photobucket.com/albums/hh275/Daniel_521/521fusebox.jpg[/img]"]http:// Thanks man but I need a pic of the diagram on the inside of the cover if you have one. I know what te fuse block looks like Quote Link to comment
DanielC Posted January 27, 2011 Report Share Posted January 27, 2011 I have one fuse box cover, and the printing on the label is almost unreadable. From outside, to inside, this is what I can read. Position 1: F Flasher Reverse Meter 10 Amp fuse Gets power from ignition switch. Position 2: A (I am not sure, could be some other letter) Heater 10 amp fuse Gets power from ignition switch Position 3: W Wiper Washer 10 amp fuse Gets power from ignition switch Position 4: C Room Radio Hazard 20 amp fuse Gets power from the battery Position 5: L Headlights 30 amp fuse. (This size of fuse seems a bit large for the gauge of wires.) Gets power from the battery Position 6: H Horn Brake lights 20 amp fuse Gets power from the battery According to the fuse cover I have, there is no mention of where the tail and marker lights are fused from. I think they come from position 6. The schematics I have of the wiring have a extra in line fuse for the taillights. I have not seen this fuse on any of the three 521 pickups I have. Thanks to dat521gather for the pictures I used in the post before this one. Quote Link to comment
laotsu Posted January 27, 2011 Author Report Share Posted January 27, 2011 I have one fuse box cover, and the printing on the label is almost unreadable. From outside, to inside, this is what I can read. Position 1: F Flasher Reverse Meter 10 Amp fuse Gets power from ignition switch. Position 2: A (I am not sure, could be some other letter) Heater 10 amp fuse Gets power from ignition switch Position 3: W Wiper Washer 10 amp fuse Gets power from ignition switch Position 4: C Room Radio Hazard 20 amp fuse Gets power from the battery Position 5: L Headlights 30 amp fuse. (This size of fuse seems a bit large for the gauge of wires.) Gets power from the battery Position 6: H Horn Brake lights 20 amp fuse Gets power from the battery According to the fuse cover I have, there is no mention of where the tail and marker lights are fused from. I think they come from position 6. The schematics I have of the wiring have a extra in line fuse for the taillights. I have not seen this fuse on any of the three 521 pickups I have. Thanks to dat521gather for the pictures I used in the post before this one. thanks man thats a big help Quote Link to comment
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