Headlights and windshield wiper motor not working?

Tiny
ALTHEA MAYBERRY
  • MEMBER
  • 1985 DODGE RAM
  • 5.2L
  • V8
  • 2WD
  • AUTOMATIC
  • 100,000 MILES
Hi guys. I have been working on this truck listed above D150 for approximately 5 years now. Y'all have helped me greatly with this project over the time that I have been working on it. I thank you for all the help you have given me thus far. I am close to being done with it so I can enjoy driving it instead of working on it.

Anyway, in 2023 I had to do a bunch of rewiring due to Negative Voltage between Ignition Coil and Battery. https://www.2carpros.com/questions/negative-voltage-between-ignition-coil-and-battery

Y'all helped with that and it's running great now. However, as I was putting the windshield wiper arms under the shroud back on, before I put the shroud back on, I decided to check if the wiper motor was working properly. But when I turned it on it did not work. Then we checked all my lights, and the headlights did not work either.

I believe I have done something wrong during the rewiring and possibly didn't get something connected back up properly. I have a 40 Way Bulkhead Disconnect diagram and a chassis electrical system diagram.

In the Bulkhead diagram it says that terminal numbers 16 and 17 go to the headlights and numbers 30 - 34 is for the windshield wipers. However, I have a feeling that the issue is not at the bulkhead terminals. I feel it is a power issue (red wire), simply because the rewiring I did was for the power, or either that it's a grounding issue. Also, the headlights and dimmer switches are brand new.

In the chassis diagram for the left headlight, it shows a G11-10WH wire that goes to ground on the chassis, and a G11A-14WH wire splices to the left headlight connector. Then from there a G11C-18WH wire, which appears to go into the windshield washer motor? And then continues with a V7-18TN wire, but my diagram doesn't go past that tan wire. Where does it go? Does it go into the bulkhead disconnect? Am I even looking at this correctly?

As for the wiper motor, I see that it grounds directly to the body by mounting. It has a V3-BN/YE, V4-18GR, V5-18BL, V6-18PU wire. Do they go directly into the bulkhead disconnect?

Summary: I did rewiring to the power (red) wires. Everything is working fine except for the windshield wiper motor and the headlights. They worked before I did the rewiring. The headlight and dimmer switches are brand new. Also, the fuses are good as well.

Sincerely,

Althea Mayberry
Friday, April 18th, 2025 AT 1:35 PM

8 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,325 POSTS
Here are the wiring diagrams and a guide to help you with the testing.

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.
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Saturday, April 19th, 2025 AT 12:39 PM
Tiny
ALTHEA MAYBERRY
  • MEMBER
  • 65 POSTS
I would like to let you know that the wiper motor problem is fixed and working fine. Though it might have help had I hooked up the wiring in the first place. LOL!

The headlights, however, is still a problem. I have no idea what I did wrong when I did the rewiring last year. I also had to put the truck in storage for about five months, so that put a big dent in my progress on getting it up and running. Now trying to remember everything I did is also an issue.

I found two blue wires under the dash which are not connected. They have round male/female connectors, but they don't go to the headlights as I have tested that idea. I have tried to connect them, but won't seem to push together. I remember that they were connected to something when I began the rewiring project, but I just can't remember to what.

I also remember that when I pulled those wires apart, there were two other wires with the same type of round connectors that went into a three part harness which fell apart when I disconnected them. I don't remember the colors of the other wires, where they are, or what I did with them. It's obvious I did something with them because I can't find them.

I guess I am just going to have to start troubleshooting the wiring for the headlights, beginning at the headlights and then working back to the switch.
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Tuesday, April 22nd, 2025 AT 6:00 AM
Tiny
KEN L
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  • 52,325 POSTS
Yep, that is a good way to troubleshoot the problem. Nice work getting the wipers working. :)

This guide we help you test for power for the headlights:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

Let us know how it goes.
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Tuesday, April 22nd, 2025 AT 11:09 AM
Tiny
CARADIODOC
  • MECHANIC
  • 34,206 POSTS
Hi guys. I wanted to make a couple of comments once this post got going. The first thing on my mind had to do with the wiper motor. There was a pretty common problem with it being dead due to a bad ground. The big clue was they would start to work intermittently if you tugged up on one of the wiper arms.

The motor is bolted to a steel plate, then that plate is bolted to the cowl, but it sits on three rubber isolators to isolate the vibrations it makes. There's a brass-colored strap riveted to that plate, then the other end goes under the head of one of the mounting bolts to make the ground. Arcing takes place under the bolt head, then the ground connection is lost. That usually starts out with the wipers stopping intermittently in mid-swipe, or they don't turn on at all one time, but do work the next time.

The common fix for that was to just add a new ground wire from the plate to the truck body. The motor's mounting bolts are on the backside of the plate so they're hard to get to, but if you have the assembly out already, it's quick and easy to add the wire under one of them. If the assembly is not removed, I drilled a small hole in the plate, then ran a sheet metal screw in it to attach the wire. On the other end, there's usually some other mounting bolt you can attach the wire to.

For your blue wires, on all Chrysler car models beginning in 1972, all dark blue wires under the hood got 12 volts switched onto them through the ignition switch when it was in the "run" position. You'll find one at the voltage regulator, one of the field terminals on the alternator, one feeding the ignition ballast resistor, and one feeding the electric choke heater. There may even be one at the wiper motor to run the "park" circuit when the wipers are turned off. If you find a dark blue wire with a black plastic triangle with three empty female terminals on one side, that was provided for optional equipment. My assumption was that was meant for dealer-installed options or for customer use, not for factory-installed options. GM did something similar by providing a single terminal in their inside fuse box.

On some Dodge truck models, I think as far back as '72 models, those 12-volt wires under the hood were red, not dark blue. The easiest way to be sure is to look at the triangular two-wire plug on the voltage regulator. The control wire will be green, (you'll find the other end of it on the second field terminal on the alternator). The 12-volt feed wire is the other one, dark blue or red. Whatever color you find at the regulator, the rest will be the same under the hood.

Good luck with the head lights and the rest of your project.
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Tuesday, April 22nd, 2025 AT 1:06 PM
Tiny
ALTHEA MAYBERRY
  • MEMBER
  • 65 POSTS
Did power light test on the fuse box. All fuses lit up except one. I'm guessing it's the one that goes to the headlights, but the words are partially worn off under the fuse. A pic is included for reference. Can you confirm if this fuse is to the headlights? I also discovered that the passenger side taillight is out.

To Carradiodoc, yes all the 12 volt wires on my truck are red. I did a rewire job on the 12 volt system last year, which you actually helped me with. However, I discovered to my dismay, that I goofed somewhere with the headlights. So I am having to trace what I did wrong.

Thea
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Wednesday, April 23rd, 2025 AT 10:23 AM
Tiny
ALTHEA MAYBERRY
  • MEMBER
  • 65 POSTS
Um, I feel kind of silly. I been tracing my headlight issue to my fuse box, but that was a dead end because the fuse box doesn't have a fuse for the headlights. The headlights have a fusible link. I still need to know what that circled fuse goes to though. However, I traced the power wire from the driver side headlight to the bulkhead, and the whole wire is hard, and the insulation is cracked. So, I guess I'll be replacing that. Also, I get continuity through the wire, but no voltage at the headlight connector.

Thea
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Wednesday, April 23rd, 2025 AT 12:31 PM
Tiny
ALTHEA MAYBERRY
  • MEMBER
  • 65 POSTS
Good news guys. I got headlights! It was a hot (red) wire issue, just like I thought. I replaced the wire from the bulkhead to both headlights, now they have power. So, headlights and windshield wipers are good to go, and I can finally enjoy driving it for a change. Thanks for all the help.
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Friday, April 25th, 2025 AT 2:40 PM
Tiny
KEN L
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YAY! Nice work, enjoy the truck :) we are here for you when you need us.
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Sunday, April 27th, 2025 AT 11:48 AM

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