1970 B Body Gauge and dash issues

[mccoymail]

Hello guys -
I'm knee deep in troubleshooting some electrical problems on my 70 Charger and though I would see if anyone could point me to a starting point/ or a restarting point to be more accurate.

What I know - Restored gauge cluster from Performance, new wiring harnesses from YO.
Started car a few months ago, everything worked as it should, gauges, lights, etc. Everyhing but the key in buzzer that is. Smelled smoke and it was coming from the key in buzzer diode, actually it was smoking. Took it out.

Picked up a used but new tick tock tach from this site, an OER unit. Hooked it up and it worked.

Started the car about a month ago and the tach stopped working, smelled smoke again. Found the tach had burned the internal board and noticed the red feed wire in the tach looks like it was wearing on the housing as the wire was pinched and has a bare spot. So I put the original clock bask in the cluster for now.

Next my oil pressure gauge stopped working. found out the my rt-engineering solid state voltage limiter is not working. Tested an original limiter and it puts out a little over 5 volts so I installed that into the back of the cluster. Oil gauge works!!! yeah.

keep in mind the cluster is not fully installed at this point, it's in the dash but not screwed in, so grounding might be questionable (just thought of that). Needed to move the car this weekend and no oil pressure on the gauge?????WTF

Also, my light switch is working, the gauge lights work but at some point my console lights and my overhead lights stopped working. Nothing at all.

Last night i jumped in the car and my map light stated working all of the sudden.Glove box light works and always has. Thinking the map light was just a grounding issue.

Now i think I have a few issues but they may all start with a root problem. Any directions?

Thanks

 

[moparnation74]

Hello guys -
keep in mind the cluster is not fully installed at this point, it's in the dash but not screwed in, so grounding might be questionable (just thought of that). Needed to move the car this weekend and no oil pressure on the gauge?????WTF

It has to be grounded.......Your dash frame to the body has to be grounded as well.....Two areas where people make the common grounding mistake.

 

[PurpleBeeper]

Man... those electrical issues are a PIA & I've had more than my fair share. Moparnation is correct....install/check all your grounds.

Based on the number of problems you've had, I'd also look for other dead-short issues like the one you found with pinched/bare red wire. It will be a lot of work, but I suggest you pull out the whole dash, both sides, and look wire-by-wire and circuit-by-circuit. You may have something shorted inside the steering column, at/near the fuse block, in the bulkhead disconnect, in the dash circuit board, in the ignition switch or in any of a number of wires (maybe more than one) under the dash.

Hopefully someone here can give more specifics, but if you may have several issues in your new wiring harness.

 

[Superb Bee]

This is the worst, I hate rally dash wiring issues, especially with new parts. That being said, I have some experience with them.

First thing is if hot wires are bare/rubbing grounded metal parts, it is only a matter of time before you have a "Car-BQ", I had a buddy who kept marshmallows in his trunk for such an occasion.

That would be the first thing I checked out and because you are having such general problems if I was doing the work, I would be pulling glass and dropping the dash. If you don't want to do that, grab a note book right down each issue and chase them down.

A wiring diagram is very helpful at this point, also as MN74 already said, GROUNDS need to be tight and right, when I do a dash I add grounds, when I restore a dash, I install a couple 8g whips on the frame before I paint it, hard to explain where but one is by the cluster and the other is behind the glove by the fuse box, so if there is an issue I know its not a grounding issue because they will drive you crazy.

I also take the connections out of the fusible link, wire across the amp meter (converting it to a voltmeter is a much better idea) ,don't plug in the cig lighter, and a few other things, I wire in a separate relay to the ignition switch also, kind of double relay the starter relay with a ford solenoid. A few little tricks not to smoke the cars but will drive the next guy crazy, lol...

good luck I hope this gibberish helps.

 

[mccoymail]

Thanks Guys -

I hate wiring for just this reason, one thing causes all sorts of other things. As I said, I'm planning on tackling some of this over the weekend and was looking for a starting point. Keep the ideas coming and I'll update as things go right(I Hope)

 

[Mr. Belvedere II]

Speaking from my own wiring experience behind the dash, I have found many times that an improper ground is often the culprit. Make sure you get the gauge cluster ground terminal secured tightly on bare metal, those gauges ground through the cluster.

 

[Mr. Belvedere II]

also the wiring diagram in The Bible helps tremendously, i soldered my pins in the back of the dash cuz sometimes they loosen in time, and for the lights i sanded the copper around the holes lightly to get a good contact with the bulb housing that and making sure things were grounded helped me resolve all manner of quirky dash proplems, im not sure how close the 70 is to the 67 but i imagine its similar though i still have the 5 volt limiter in line with the gauges, 70s might be 12v not sure. hpoe this helps

 

[Mr. Belvedere II]

One more thing and I'll shut up already! i remember that i didn't want to rely solely on the "cluster to dash" mounting screws as my ground, i used one of the cluster screws that runs through the back of the cluster to the plastic trim bezel and ran a good 14ga wire to the body to make for permanent ground. there is one right at the corner of the cluster that is what I used

 

[Shorthorse]

Keep in mind, unlike dash lights, interior/courtesy lights have constant power at all times. They operate via a switched ground.