poncho power

My 68 dash has a circuit board on the backside, so you can't plug them in the wrong spot. I didn't get a chance to work on it today, but I will dive into it tomorrow... I'm wondering about the dash having a good ground also, I will have to see if I can find it...

66 Gas Tires Oil

your not understanding it. the negative comes from the temperature sending unit. dash is not in the equation it just supports the bulb in this type of circuit. there are two wires going to the socket. pos from the key and neg from the sender. read my posts untill it sinks in otherwise take it to a mechanic and have him show you how it works consider it paid training. for some folks, electrical devices are hard to undertand but that is ok you got to start from somewhere. good luck.

jim

poncho power

Yes, I do understand it, BUT, I already grounded the temp wire to the Bat ground, & the light does not come on. I will dig more into it today.

poncho power

SUCCESS! Found a connector under that dash that was not good anymore. Someone had cut and spliced a ground wire. I had the temp sender wire grounded to the battery, & then I went under the dash and started moving wires around, when all of a sudden saw the light flicker.... sure enough the wire was barely holding on to the butt connector. Repaired the connection, and now it works..... thanks for the help on that one.

gjones

Excellent news!!! Wiring mods. done by PO's will always get you in the end! Most times it usually IS a rusty/bad ground that is the source of consternation, though!

PontiacJim

You say the last owner painted the firewall. He may have disturbed some wires or removed them to paint. I learned this one my self - make sure you have a grounding strap from the engine to the firewall. The factory one, as I recall, is a braided strap. You mentioned this, check to see that it is not broken, corroded, or the attachment bolt/screw stripped out on the firewall from over tightening. I was having a problem burning out voltage regulators. Finally figured that one out. I was the one who pulled the ground strap off when I rebuilt the engine. A Ground strap is very important. I also experienced on another GTO an Alt light problem. I found a broken wire inside the plastic casing in the engine compartment. It looked perfect on the outside. Used an Ohm meter to test the wires, one at a time, going from the engine side to the dash side. Tedious, but that's how it is done sometimes.

poncho power

Jim....
I got the temp wire repaired, so that light comes on now when I ground the wire at the sender.
I still have an issue with the BAT light not coming on all the way with the key in the ON position. It has a real faint glow, just enough that I can see the light on. When I start the engine, the light goes all the way off, and the engine is charging. I still wonder why that light only comes on faintly when I have the key in the ON position though...?

gjones

That sounds like a grounding problem to me. On the '66, at the rear of the dash, there is a metal grounding bar that attaches to the steering column. I forgot to tighten that up securely and had very strange dash light operation. Was a really quick and easy fix. Not saying that's your problem, but it may be worth a look. Also, have you pulled the fuse box and inspected the terminal ends and connectors? Mine were RUSTY. Took FOREVER to clean and deoxidize, but well worth it, saved a bundle of cash, and after all said, was gratified to still retain the original wires (NICE) and fusebox, with fresh loom tape. I also installed 4 new engine to frame/firewall/body ground straps. All is swell in electric land. And as Pontiac Jim said, check those old wires laying on top of the engine going to the alternator which have heated and cooled 100,000 times. They get mighty brittle after 45 or so years. May the Pontiac gods smile upon you!