Atlee Posted October 18, 2021 Share Posted October 18, 2021 I picked up a 1987 Comanche 4.0 5 speed last week. The following is a list of the stuff that didn’t work. blower motor, radio, clock and turn signals. I checked and cleaned all the fuses under the dash. There were multiple blown fuses so I replaced them. After replacing the bad fuses everything worked I had blinkers, clock, radio and the blower. Last night I noticed my dash lights where out when I turned my headlights on. then as I was driving my windshield wipers cut out. When I went to drive to school this morning I noticed I also now have no turn signals or radio. I just checked all the fuses under the dash again and non of them are blow. The blower motor and hazards are the only things working. Notes: Sometimes radio flashes on for just a second when I turn the truck off. Clock only worked if I didn’t have the headlights on. when I first “fixed” the blinkers it would take a solid 2 seconds after hitting the switch for the dash indicators to work and they would speed up faster and faster the longer I had the blinker on. Also there was a time when the blinker was blinking but very erratic and dim (on dash). Link to comment Share on other sites More sharing options...
MiNi Beast Posted October 18, 2021 Share Posted October 18, 2021 Check flashers, relys, plug connectors for corrosion. Check for brake fluid leaking on the fuse panel from the slave. Link to comment Share on other sites More sharing options...
Pete M Posted October 18, 2021 Share Posted October 18, 2021 after the aforementioned items, I would then do all of Cruiser54's MJ tips and the headlight relay. should be links to both in here: https://comancheclub.com/topic/13447-what-is-the-most-important-tip-youd-share-with-mj-owners/ Link to comment Share on other sites More sharing options...
howeitsdone Posted October 19, 2021 Share Posted October 19, 2021 Exactly what they said. All of those items splice together. Make sure to check your chime module on the left of fuse panel and fuse pins for corrosion. Fuses may be fine, but you may need to remove corrosion from the pins on the box itself. The wiper circuit breaker is on the bottom and also can be effected by brake fluid and water over time. Disconnect battery when doing so to be safe. Otherwise, it may be a ground issue. You'll want to check the C102 connector behind the front left headlight. Unplug it, not the easiest thing to do. To help, you can remove the parking lamp and pull the connector through. You'll need to clean it and that will give you the most room to work with. If you have a multimeter it really helps to narrow down paths to the issue. The parking lamp socket grounds go bad. Cruiser54's tip #3 shows this plug. The ground is located in front of the washer reservoir on the side of the fender. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 19, 2021 Share Posted October 19, 2021 Ignition switch is burned at the fat brown wire. Link to comment Share on other sites More sharing options...
Atlee Posted October 20, 2021 Author Share Posted October 20, 2021 update: today I went around and cleaned up all the grounds I could find in the engine bay. I also cleaned up all the relays. This only fixed the clock but it still won’t work with the headlights on. I haven’t cleaned the fuse panel clips yet but I don’t think that’s my issue. I used my multimeter and it turns out I am not getting any power to my fuses for the blower, wipers, turn signals, or dash lights. So this makes me wonder if all these get power from a single wire? If so anyone know what wire it might be? Link to comment Share on other sites More sharing options...
AZJeff Posted October 20, 2021 Share Posted October 20, 2021 1 hour ago, Atlee said: update: today I went around and cleaned up all the grounds I could find in the engine bay. I also cleaned up all the relays. This only fixed the clock but it still won’t work with the headlights on. I haven’t cleaned the fuse panel clips yet but I don’t think that’s my issue. I used my multimeter and it turns out I am not getting any power to my fuses for the blower, wipers, turn signals, or dash lights. So this makes me wonder if all these get power from a single wire? If so anyone know what wire it might be? You need a wiring diagram for the 1987 model year. I have one for the 1988 model year, if it is applicable. Others on this forum can confirm if it would applicable to your needs. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 20, 2021 Share Posted October 20, 2021 Brown wire at ignition switch powers everything you don't have..... Link to comment Share on other sites More sharing options...
Atlee Posted October 20, 2021 Author Share Posted October 20, 2021 Thank you cruiser54. Just went to start the truck up, turn the key… nothing not even a click. Try 3 more times then suddenly boom fires right up like nothing happened. Will definitely be taking a look at the ignition switch now. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 20, 2021 Share Posted October 20, 2021 so now what ya gonna do? Link to comment Share on other sites More sharing options...
Atlee Posted October 20, 2021 Author Share Posted October 20, 2021 You couldn’t have been more helpful! Pulled the ignition switch and look what I found! Does this mean I had a short in my ignition switch, therefore replace both it and the plug or should I try just the plug first? Link to comment Share on other sites More sharing options...
cruiser54 Posted October 20, 2021 Share Posted October 20, 2021 Just means that circuit has too big of a load on it. The way it was designed. Now, get all your grounds cleaned up using Tip1 on my website. Then, do the blower motor ground upgrade in one of the other Tips. Glad you found it. Link to comment Share on other sites More sharing options...
Bombout800 Posted October 25, 2021 Share Posted October 25, 2021 Man this is awesome.I'm glad you got it figured out! It would have drove me absolutely crazy 😂 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now