So Tuesday morning started the truck put it in reverse and blink, charge light came on. No aux. lights work, gas gauge and temp gauge don't work. Seen this before, Alternator, right?

That's what I thought until I replaced it and it didn't fix a thing. Now there is no guarantee auto parts store parts work every time, so going to have my old one checked tomorrow. So in case it isn't the alternator, any suggestions on what else could be causing the problem?

It's an 85 base model w/ AC and carbureted.

Thanks

 

Update. Took the alternator off and had it tested. It's working fine. Tester said battery was bad. Replaced it, still same problem. Checked all the fuses and non are blown. Wiring looks to be in good condition, so I'm wondering if it's wiring somewhere else causing the problem. Gonna check the tailight wiring since when I put it in reverse is when it all started.

 

No I haven't done anything to it in awhile. Yea I was going to trace connections today. Probably start with the taillights since it's when I put it in reverse that this all started. Anyone know where the reverse light switch is on a 85 manual?

 

Ok, so my volt meter had a continuity check setting so I know all the connections to and from the alternator and battery and good. Even checked the ignition switched wire and grounds. There is a red wire coming off the alternator and going to the fuse box in the drivers foot well. It has continuity also. Other than the foot well, under hood and the 2 fuses behind the glove box are there any other fuses?

My hanes manual lists a gauge and turn signals fuse, but I can't find them, any ideas if these existed on an 85?

 

Yea, I'm thinking it's something with the other side of the fuse. All the wiring to the dash. The grounds under the hood all test fine.

 

Any one know where the reverse light switch is on a 5 speed manual 85 2wd?

 

Should be on the side of the trans!

 

Yea I found the switch. It seems ok, both wires going to it had continuity to the frame. I was checking it, cause it was when I put it in reverse is when all this started. The reverse lights are fine, checked them this morning.

 

According to my diagrams, it's on the same circuit as the charge light. Along with the turn signals, gas and temp gauges, and windshield wipers. All of which don't work. My diagram does show some fuses though that I cannot locate anywhere.

 

OK, took dash apart. Found all wires on this connection. All had continuity to fuse block and all grounds to ground. Even found the reverse switch and it checked out fine.

So I'm back to the alternator. Any one point me in the direction to test it's output while it's on the truck? My manual is fuzzy on how to do this and keeps saying to ground some node that I can't see and if it's the one I think it is not sure how in the world to do it while it's on the truck.

 

Ok, so the only thing I did, other than taking it all apart yesterday and putting it back together was to plug the seatbelt warning switch back in. This has been unplugged for a good 3 years. And halfway to work, about a 10 min drive, the charge light goes out, the seatbelt light flashes on for maybe a second and then it goes out and bam, gauges work, blinkers work ect.... IDK!

 

Update: It's been working on and off for last couple weeks. Never know what it's going to do.

Anyone have any tips on how to test the alternator while on the truck?

I'm going to unplug it and fashion my own connections to the back of it and test the outputs. Only thing I can think of. If it's not putting anything out it's got to be bad regardless what autoparts store tester says.

 

Simple volt meter to the battery posts will tell you if its charging or not. Anything above 13 volts is good but 13.8-14.4 volts is ideal.

 

You couldn't have been more right. Light went off on the way to work today. It was a slow day at work. Wondering around chatting waiting for out part to go out so we could work again. I design memory chips. Just ran into a guy I work with often and just started bs ing and I mentioned my issue. First thing out his mouth was the ignition. Thought maybe, he's a car guy too and has had many issues in his time.

So left work, hoping light would still be off so I could probe around with voltmeter when I got home. Well, of course not. So driving home fuming, it came back to me, ignition switch. The second I even put pressure on the key to wiggle it, charge light went out, seatbelt light came on for brief moment then went out and all gauges and signals worked.

I'm getting 13+ volts when light is off, so alternator is working. Shut it off. Had to run some errands with wife. After dinner I went back out, started it and sure enough light was on. Wiggled key and presto light goes off.

So I've taken the ignition all apart and looked it over and it's got some minor looseness to it but nothing crazy. I put it all back together making sure all connections were tight. Seemed to work fine when I started it.

Side note: Donned on me today. When charge light is on and truck is running if I open the door the buzzer goes and goes. When the charge light was off and the truck is running if I open the door no buzzer. After disassembling the ignition and putting it back together, the buzzer sounds while running and the charge light off.

So you were right. Right under my nose, while driving. Guess if it keeps it up I'll replace the ignition switch and key cylinder.