tpawlik

A friend and I duplicated the complete original wiring harness. All connections were soldered or crimped. We have landed or have accounted for every wire.

However, we have some issues.

1. Some of the small lamps in the instrument cluster are not as bright as others. The speedo lamps are very dim. The Generator and Hot lights are very bright, but they get their power from the ignition switch. All of the bulbs are new.

2. With the headlight switch on, the right two tailights are dim. The left two tailights are very bright because both elements in the bulb are illuminated. Not correct. Only one element is on until the socket is connected to the tailight housing then both are on. The right tailights stay dim, regardless of them being connected. Sockets and bulbs are new.
TYIA,
Tom

rocketraider

Check the orientation of the power strips in the socket base to make sure they're properly indexed with the ground sleeve. If the lamp is rotated even slightly out of alignment it will cause problems such as you're seeing. Those damn taillight sockets from that era were a notoriously unreliable design and I never understood why GM used them as long as they did. New chinesium parts are no better.

We got a brand new repop taillight harness for a friend's 64 Grand Prix because we were tired of messing with the faulty original, and danged if we didn't get one that had a wonky socket that did what yours is doing.

What was the cluster lighting like before the rebuild? and did you use the lamps it called for? Have you checked or cleaned the dimmer rheostat coil? or have you taken the cluster itself apart and cleaned it internally? Did you clean or scuff the connector pins on the printed circuit?

tpawlik

Rocketraider,
I'm not too crazy about the quality of the replacement lamp sockets either. I will check the contacts with the ground sleeve.

My car is a convertible that sat for a while with no top. The instrument cluster I am using came out of a hardtop. I bought it because it was in better condition and had the Speed Sentinel feature. The lamps are the correct lamp according to the service manual. The headlight switch is new and the rheostat works. I disassembled the speedo unit and cleaned it. I did not clean the pins on the printed circuit. I will try that next.
Thanks.

chequenman

Try cleaning Circuit Board with blue or grey colored Scotch Brite Pads if you can find them. They leave the least amount of residue, then with really low air presure blow off the Board. That's also good to check that you're installing the correct Numbered Bulbs, as they can get mixed up over time.

Lady72nRob71

A pencil eraser works for this also.
Check to make sure all your grounds are connected. If something is grounding through a component and not a wire, dim lamps will occure.

tpawlik

Thanks to all that replied, especially Rocketraider. I pulled the bulb retainer out of the two left hand tailights and rotated them 180 degrees and the lights are miraculously working as they should. I would never have figured that out.

Regarding the dash lights, I did clean the pins on the main connector and polished the surfaces that the socket contacts as well as the sockets. No change. Since I do not have the dash completely installed, I'm hoping a solid ground is the problem as stated by Lady72nRob71.

I will let you know when I get the dash bolted up all the way around.

Thanks again.