Electrical short in dash, where should I start?

[Adam Connell]

Well, this has been an issue with my car as long as I've owned it but it's gotten worse. When it's cold outside (below 60) every time I hit a bump, the voltage light comes on momentarily. Watching the scan master, the same thing happens, the voltage drops as low as 11... once the car warms up, it seems to go away.

So last night for some odd reason, it was being especially picky, and I knocked on my dash! Sure enough, when I knocked I recreated the issue. So my guess is I have a short in the dash of my car.

Now since it's a PITA to get back there, I figured I would see what other's thought before I tear it apart. Im stoked that I finally found the issue though, it's really annoying!

 

[TWISTER]

Prolly just a loose bulb or connection there. The bulb is in series to complete the curcuit for charging. Caspers makes a kit to remedy this to keep it from failing to charge. Its called alternator field fix if I remember right.

 

[Red C5]

I'd try to look under for anything obvious or a loose wire, etc. Chasing electrical gremlins can be a PITA. Good luck getting it sorted.

 

[TURBOTWIN2]

Maybe clean the ribbon strip of electrical circuits with a pencil eraser after you pull the speedo head out. Also, as TWISTER says, pay close attention to the charge circuit bulb and the connector it fits into, as the alternator will not charge without it completeing the circuit.

 

[charlief1]

If you don't have the wiring diagram send me a PM Adam with your email. I'll send you the diagrams so you have a better idea of what you're up against.

 

[chopped39]

Prolly just a loose bulb or connection there. The bulb is in series to complete the curcuit for charging. Caspers makes a kit to remedy this to keep it from failing to charge. Its called alternator field fix if I remember right.

X2 that happened to me when I got my car back from the dealer back 89. After 2 alternators they installed a printed circuit board and then never tightened the cluster screws
You can have the cluster out in no time.Get the Caspers kit.

 

[Roger]

X2 that happened to me when I got my car back from the dealer back 89. After 2 alternators they installed a printed circuit board and then never tightened the cluster screws
You can have the cluster out in no time.Get the Caspers kit.

Caspers field fix kit does not require any under dash work. The kit is installed under the hood & I took less than 2 minutes to install it.

 

[Adam Connell]

Haha sounds like I need to get the caspers kit. I got it mostly torn apart last night, but the farther I dug the scarier it started looking.

I still am either A)not pulling hard enough or B) have not removed enough to get the analog cluster out... Im about to go wrestle with it some more.

Either way, it sounds like the caspers kit is a nice solution to a factory flaw.

 

[TWISTER]

The cluster wont come out as the speedo cable holds it in. you should be able to access the bulb and check it out for looseness though. The caspers kit is a real headache saver in the longrun. If it saves your a$$ once its worth it. I think its around $40.

 

[Adam Connell]

OK got her all buttoned back up.

My diagnosis... Loose connections! I took it all apart, jiggled everything around, and found nothing wrong. Cleaned a few connectors, removed and reinstalled all of the dash bulbs, and I replaced the fuel pump fuse and the cig lighter fuse.

Car now sits at 13.8-14.2V on the SM! No more blinking light.

I do find it odd though, the FP and Cig lighter fuse didn't let go until a day after I put it all back together... Seems they were a weak link, and most likely original. Also the car never got above 14v on the SM before I replaced the fuses. The FP 15 amp fuse went, replaced it, and then less than 10min later the cig lighter fuse went... Now everything is much happier! No issues to report and the car once again seems to have found new life. Every electrical gremlin I fix seems to take years off this car... Scary thing is: I always thought everything was running ok!! Now I know better...

Thanks for the help guys, I will be ordering the casper's field fix with my next paycheck!