No dash or dome lights

[flyboy1100]

Thanks, I tried squeezing it but I guess not hard enough. The plastic is getting old and brittle, so you know I didn't want to break it

Sent from my SCH-I605 using Tapatalk

 

[chengny]

Go ahead and squeeze it. What have you got to lose?

What would rather have; a pretty but non-functional dome light or one that's ugly but works?

Even if you break it, you can get a new one. Those dome light covers/lenses aren't expensive or hard to find.

Or - you could check the dome light circuit for power with a meter.

Push the seat forward and tilt the backrest towards the steering wheel.

If the LH (driver's side) stock speaker/bracket is still in place - unscrew it and move it aside. There is a void space in the B pillar that as an access opening at the bottom:

You must be registered for see images attach

The wires that lead up to the dome light come out from under the floor mat/carpet and enter the B pillar at the bottom. If you reach in and fish around, you should be able to feel the dome light wiring harness.

There is some slack, pull the wires out. There should be a 2 wire male/female plug connector in the harness right there. Separate the connector and check for 12VDC at the lower side of the connector (the wiring that comes out from under the carpet).

Should show voltage with either door open, both doors open, dimmer rheostat turned all the way CCW or any combination of those.

 

[flyboy1100]

it works with the light switch, no need to remove the lense.

I'm guessing the door switches are shot.

maybe this weekend I can finish this and get my dash back in

unrelated to the dome light. do you know what the Gray w/ black stripe and brown wires are for the dash lights? they are connected to a bulb holder, but I am not sure where it is supposed to go back to...

 

[chengny]

Bulb sockets that are not plugged into the pc board ( separate plastic sockets that have no copper contact tabs & 2 wires connected ) are generally used for optional equipment.

From what I have seen over the years, these are usually used for 4WD indication (with a NP205 T/C) or a check engine light.

If you have any lamps of these type, they are usually mounted behind a small, add-on display console (above and between the speedometer and gas gauges):

You must be registered for see images attach

The back of the display has two twist-lock penetrations that accept these optional sockets. They are different sizes.

If you have one of these extra display windows, see if your stray bulb holder fits in either one of the holes.

If it does, shine a light from behind and see what is etched on the plastic window. That should give you a good indication of what system the bulb is associated with.

Other than that, I don't know. I went through a ton of schematics looking for a twisted pair colored as you describe - and found nothing.

Does your truck have any unusual optional equipment?

 

[flyboy1100]

Not that I know of, seems pretty standard; k1500 (k10?), 305, 700r4, np208. I don't even have extra lights/spots in the circled location above. Im pretty sure I remove it when I took the dash out, guess I will do some more looking tonight.

Where can I get good wiring diagrams for an 86? Chilton is worthless.

Sent from my SCH-I605 using Tapatalk

 

[flyboy1100]

No idea where i got gray/black stripe from, it is 1 white and 1brown..i have the electrical diagrams now so i can look it up. Thanks for those btw, some of the other stuff you shared had been taken down though

Sent from my Nexus 7 using Tapatalk

 

[flyboy1100]

brown and white wire are for the 4wd indicator. kinda weird that the traces are there on the printed circuit for it, but no pin in the connector. oh well.

got the fuse box apart, everything inside looks to be connected well, so either something got loose, or there is a break in the green wire somewhere. i will probably just cut in a splice between the switch and the back of the box and call it a day as a preventive measure

just need some new bulbs and i should be in business!

 

[Toddd]

Kind of the same issue

So I had my cargo light working and power to the dome light (no bulb) when I went to sleep last night. I get up this morning and I have no power to the dome light o cargo light. So I checked the power at the panel and I have no power coming from the panel to the orange wire going to dome. I had power last night. The light under the dash works and the door push button turns it off and on. How is it that I lost power to that portion of the panel? None of the 6 "battery" slots on top left portion of panel have power now. I read something about checking the HL switch? Please HELP!!!! Thanks in advance. Its a 1987 R10.

 

[chengny]

Check the fuse labeled HORN/DM. That fuse supplies the 6 sockets in the two battery banks above it - as well as the orange 240 circuit.

If the fuse is good, leave it out and check the line side of the fuse socket. I'm pretty sure the line side is the inboard /RH side of the socket - but to be sure, check both sides. One of the sets of fuse clips is wired straight to the battery and should be hot at all times.

If neither clip shows 12 VDC, you must have melted a fusible link somehow.

The lead that feeds the BATT bank - and the 240 orange circuit (i.e. horn, dome/cargo lights, clock, etc.) - is not the one that passes through the firewall junction block. There is only one fusible link in that feed - it's one of the two down at the solenoid. So don't expect to see the one at the JB melted.

 

[Toddd]

Thanks!!! It was blown horn fuse. But what caused it to blow? Fuses just blow out? I havent put another one in yet but when i do and if it blows immediately, should i check my grounds? I dont currently have a horn installed. Would this cause an issue?

 

[chengny]

should i check my grounds? I dont currently have a horn installed. Would this cause an issue?

Poor ground connections can cause a lot of problems - but blowing the fuse that protects the circuit is not one of them.

Not having your horn connected wouldn't cause the fuse to blow either. Nobody was in the truck beeping the horn during the night - right?

What is strange about this scenario is that it happened while the truck was sitting still in the driveway. Normally a short that blows a fuse happens either immediately after replacing the fuse or while driving on a bumpy road.

Were you doing some electrical repairs on the dome/cargo lighting circuit earlier in the day? I have to ask that question because you start your initial post with this:

So I had my cargo light working and power to the dome light (no bulb) when I went to sleep last night.


This is just my experience - but I have found over the years that if a new problem suddenly develops, it is almost always related to the last thing you did. Check your work if this is the case.


Another thing to look closely at is the wiring to the cigarette lighter (and the lighter socket itself - if it still exists). The lighter is on the orange 240 circuit and it is notorious for developing a short to ground. As a simple test, just unplug the single lead that connects to the back of the lighter. Then, with the lighter unplugged, replace the fuse and see what happens.

Other than the horn (control circuit only) and the cigarette lighter - both of which are hard wired to the fuse block, there are only two other accessories that are supplied by the fuse that blew. Those other two accessories are the dome/cargo lights and the clock (if installed). Both of these use plug-in type connectors at the fuse block.

So if you continue to blow the HORN/DM fuse, try unplugging the leads for the dome/cargo lights & clock one at a time and see if a pattern develops.

 

[Toddd]

I did just replace the wiring harness from the fuse box to the dome switch behind the seat to the dome/cargo light. I'll recheck all connections but im pretty sure they were all white to white and orange to orange. Whats weird is that they were all working when i last closed the door. I got up in the morning and they didnt work and the fuse was blown. Thanks for all the help. I'll let you know what happens when i replace the fuse after church.

 

[Toddd]

You post said "driving down a bumpy road". Maybe when i shut the door, something happened. I have to shut it pretty hard for it to close properly.

 

[Toddd]

And there is no lighter in the truck. And no horn.

 

[Toddd]

So i replaced the fuse. It blows immediately. I disconnected all plugs from fuse box to dome light switch/dome light and cargo light. Working from fuse box i plug them back in one by one and they dont blow until i insert a bulb into either socket. Wrong bulb? Bad sockets?