View Full Version : goofy electrical...

03-08-2009, 09:55 AM
I'm thinking it's a ground issue and hopefully these things are related to one ground. that's likely not the story But I can hope.

several things suddenly started acting strange. Like...

1. fuel guage doesn't work when starting up the vehicle, sometimes it'll kick on about 20min. after driving...sometimes not.
2. temp guage...similar scenario, but works more regularly
3. wipers no workie.
4. left turn signal indicator will light, but no flashing. rear indicator lights, no blink. Hazards flash, but not the front left. Right side works fine.
5. Horn no workie.

Things I've done:

removed, cleaned and re-ran a ground wire from Left front signal. no change. but it's all cleaner.

horn didn't work about a year ago, I replaced the horn relay then it worked for a while now... no workie...used to work. then stopped.

Haven't messed with guage stuff at all.

Any advice on which ground(s) to maybe start chasing down??

03-08-2009, 10:32 AM
probably a ground issue for the temp and fuel gauges:

The horn has a contact that wears in the steering wheel. pull the wheel cover that has the buttons off and check it out..

03-08-2009, 04:22 PM
Rover thanks for the reply...I neglected to mention...for the Fj40. for the record, if it was the 60, you'd be right on the money. Sorry to miss that oh-so-important fact.

Update: gave a super powerwash, got out the electric contact cleaner, tightened various connections and now...flashers, fuel and temp guage working fine. still no horn, but I now hear the click of the relay. no wipers, but I'm going to clean up the fuse block before anything else. I'm suspiscious that the contacts are corroded/dirty.

03-08-2009, 05:48 PM
electrical is evil and bad....i wish you luck. i just spent a bunch of time diagnosing my gps power cord only to find out the gps itself has gone south:(

03-08-2009, 10:23 PM
Take the entire fuse block out and clean it. I started doing that as the first thing when I brought a 45 home and it saves a lot of time.

03-09-2009, 09:12 AM
I've got similar gremlins in my 40 for fuel and temp. I replaced both sending units - that fixed the temp gauge, but not my fuel gauge. For the fuel gauge, I believe I have a short in the instrument cluster somewhere. I've had it out a few times, and once managed to wiggle the wires in just the right way to get the fuel gauge to work, but after a couple weeks it reverted.

So all that said, if both sending units have been determined to be functional, then I'd pull the instrument cluster again and see if you can find any wiring shorts in the gauges themselves.

03-09-2009, 09:33 AM
What year 40? The new style instrument clusters do have an issue with the contacts breaking at the solder points. Re-solder and that will take care of that one.

03-09-2009, 10:11 AM
It's a 77FJ40...and the oil-pressure guage hasn't worked since i got it even though I replaced the sending unit and Robbie swapped guages a while back when he did a bunch of work on it.

I think I should bite the bullet and pull the cluster to replace all the bulbs, check the connections, fix the odometer, etc... Add that to the fuse block project. I'm just praying for big blizzard so I can hang out in the garage. :-)

Air Randy
03-09-2009, 10:27 AM
Be sure and check the large ground cable that goes from the battery to the engine block. On my 40 i was getting the same clicking on the horn relay. I cleaned the connection on the ground cable from the battery to the engine block and that improved it but not 100%. I then added another ground cable from that same point on the engine block over to the frame with good clean connections. That fixed my horn and a lot of other minor electrical gremlins similar to what you are experiencing.

The only other thing I did was replace the mechanical flasher with an electronic flasher, made my turn signals work much better. You can use any 2 prong electronic flasher. I bought one at AutoZone for $5.

03-09-2009, 01:28 PM
My fuel and temp gauges don't work either sometimes. But sometimes if I tap the instrument cluster they come back. I tried a different instrument cluster backplate (with all the soldered pins and electrical runs) and it still did it. So I think I have a short somewhere in the wiring, which I'm not excited to track down.

Good luck.

If your turn signal flashes once and stays on, then that means you have a bad bulb either front or rear. Sounds like your front bulb is bad.

03-09-2009, 01:41 PM
That's exactly what I thought was going on with the flashers...replaced the bulb, and no workie. Then, I pulled the offending unit off the fender, cleaned the contacts, ran a new (what I thought was the ground), cleaned the under carriage and engine bay real good...now they work fine. I dunno...I'm chasing grounds and cleaning up the fuse block for the first go-'round.

I hate chasing electrical gremlins.

03-10-2009, 06:11 PM
Be sure and check the large ground cable that goes from the battery to the engine block.

FYI, A stock 40 series has no ground from the battery negative terminal to the block. The battery ground goes to the frame near the fender mount, and a separate large gauge ground goes between the frame and one of the starter motor mounting bolts, which grounds the block to the frame and thus to the battery.