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My ('84 720) Headlights dont work


JuanOch0a

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Hey guys, I have been trying to work more on my truck and almost everything is done but my concern on my truck is my headlights. They dont turn on, neither in low or high beam, but all turn signals, side markers, and tail lights work. I tried testing the bulbs and they're fine. I turned on the the headlight switch and I tested with some wire and a light tester the connector they connect to to see if that was the problem. I put my piece of wire into the ground part was and I put another piece to the positive terminal of the battery. The light turned on, but when I took off the positive wire from the battery and inserted it into the drive part of the connector, the light did not turn on, (note, the switch was still on, to clear confusion), long story short, the ground on the connector works but the pass nor drive connections pass anything. Would really appreciate some help on this

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Check the last two fuses on the far right of the fuse box. They are both 10 amp. They should read battery power on both sides.

 

If not, find the 3 fusible links attached to the positive battery cable. They are about 4" long with plastic connectors on the ends so they can be removed and replaced. There is a Green and a Red together and a single Green by itself. The single Green by itself it the one you want to check. It may be burned and crispy, or it may look OK but test it for +12v.

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19 hours ago, datzenmike said:

Check the last two fuses on the far right of the fuse box. They are both 10 amp. They should read battery power on both sides.

 

If not, find the 3 fusible links attached to the positive battery cable. They are about 4" long with plastic connectors on the ends so they can be removed and replaced. There is a Green and a Red together and a single Green by itself. The single Green by itself it the one you want to check. It may be burned and crispy, or it may look OK but test it for +12v.

Like these

https://m.facebook.com/story.php?story_fbid=115869403281279&id=100045746596686

I also looked at the 10 amp fuses, they dont have anything and there was only one, and th that one looked very corroded. I also looked near the battery and found some sort of relay, I checked the connection on the plug in and they all came to show around 3-5 volts, except for one which showed almost 10. Could that be the problem?

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Sorry I certainly do NOT use f/b. Some do but I don't.

 

Get a picture hosting site account, (ANYONE BUT PHOTOBUCKET) there are free ones. Download you picture(s) there. When you want one, go there, copy the picture information, come here and past it into your post. So everyone can see it.

 

Replace the fuses with 10 Amp.

 

I'll have to wait for the pictures of the fusible links.....

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46 minutes ago, datzenmike said:

Sorry I certainly do NOT use f/b. Some do but I don't.

 

Get a picture hosting site account, (ANYONE BUT PHOTOBUCKET) there are free ones. Download you picture(s) there. When you want one, go there, copy the picture information, come here and past it into your post. So everyone can see it.

 

Replace the fuses with 10 Amp.

 

I'll have to wait for the pictures of the fusible links.....

20200119-120548.jpg20200119-120551.jpg20200119-120520.jpg20200119-120817.jpg20200119-120502.jpg

How are these?

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Bedda.

 

20200119-120502.jpg

 

These are the fusible links connected to the positive battery terminal.

 

22 hours ago, datzenmike said:

 

 

If not, find the 3 fusible links attached to the positive battery cable. They are about 4" long with plastic connectors on the ends so they can be removed and replaced. There is a Green and a Red together and a single Green by itself. The single Green by itself it the one you want to check. It may be burned and crispy, or it may look OK but test it for +12v.

.

 

Someone has replaced them and used crimp on terminals. Just look how crappy those connections will be. Check for 12v on the end of the Red wire and the White/Black stripe and the other one. If no power clean and re tighten those connections. Fixed, this should give you power to the two 10 amp fuses.

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46 minutes ago, datzenmike said:

Bedda.

 

20200119-120502.jpg

 

These are the fusible links connected to the positive battery terminal.

 

.

 

Someone has replaced them and used crimp on terminals. Just look how crappy those connections will be. Check for 12v on the end of the Red wire and the White/Black stripe and the other one. If no power clean and re tighten those connections. Fixed, this should give you power to the two 10 amp fuses.

That's some good info, but can you tell me what that relay is for and where I can get another? I've looked everywhere but since the sticker that has the part # wore out my usual ways to find things aren't working. The relay was right next to the battery and screwed to the side. 

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