The coolant temp gauge didn't work on my '87 XJ6 when I bought it. I determined it was a broken wire/bad connection between the sending unit and the gauge so just ran a cheater wire from the sending unit direct to the gauge so I could drive it without imagining imminent engine destruction. With several hours of fruitless wire tracing over several attempts I finally tracked it down to a multi gang connector under the air cleaner that was a bear to pull apart but I finally got it and it had a case of the cruds. Got it cleaned up and now have connectivity from the sending unit to the gauge. Huzzah!

 

Hey, great work. Tracking down electrical issues can be frustrating, but a methodical hands-on approach usually wins. Fuses, relays and even globes can be substituted with known good to isolate faults. Worst case I had recently was on a late model Ford Territory with an intermittent door courtesy light. At rest, it performed faultlessly but, hit a tiny bump, it didn't. Short answer . . . the filament was still good but dislodged at one end, so it worked most of the time, except when it didn't! Galvanised me into replacing all with LEDs.

Cheers,

 

Two things that hindered me were #1, the wiring diagram just showed a 1/2" line from the sending unit to the gauge with no hint of connectors in between and #2, somewhere over the years the wiring color changed. Yes, intermittent faults can lead to serious frustration.

 

It doesn't help when you discover you have an intermittent fault with your multimeter. Checking continuity on something the other day, I looked down at the probes on my meter to observe the black lead was close to falling apart. Grrrrrrrr!

 

If that plug & jack is gooped up with corrosion, you can best bet you have others. I would advise you methodically go through ALL the P's&J's and clean them also. Don't do all at once - you don't want to create a troubleshooting nightmare. One by one.

Bill

 

Oh, an "Intermittent!"
What Fun!!
NOT!
But, You Have PREVAILED!!!
(';')

 

Great advice. That is in the plans. My voltage gauge runs a bit low though I'm seeing good output at the alternator, probably the same cause. Of course, my synapses aren't firing like they did back in '87 either.

 

LOL . . . I suspect you have spoken for many of us here, so perhaps this warrants a STICKY ???
Just jokin' but I love it . . . now, if I could just remember why . . .

Cheers mate. You have brightened our day!