My warning lights sometimes work, mostly after running and driving the car for awhile. I have a 87 FC, I know the cluster works cause all the lights light up and then turn off when i turn the engine over. Anyone have ideas why they only work sometimes?

 

Corroded connections perhaps? With the age of our vehicles poor connections and resistance can wreak havoc

Good luck!

M

 

This problem is likely caused by corroded or poor quality solder joints on the CPU (black body control module behind the kick panel to the left of the dead pedal in the driver's footwell on USDM cars.) It could also be corroded solder connections on the idiot cluster itself. The repair is straightforward and fairly simple. Remove the units, disassemble, De-solder, clean, re-solder, and re-assemble.

 

sLEEP,

If you are having intermittent problems with all of the warning lights then there may be a cold solder joint problem. I would like to add to DaBrkddy's recommendation: check the Warning Light Cluster for cold solder joints first. The probability that the Body CPU is causing all the warning lights to intermittently fail would be lower than the Warning Light Cluster. The Warning Light Cluster, much like the logicon, is known to suffer from cold solder joints. Refer to Diagram C-3 in the WDM (Wiring Diagram Manual). Section T in the FSM will show removal/install procedures.

The next question to ask: how confident are you with a soldering iron?

Cheers,
George

 

Just a thought, would it affect the warning lights if my battery gauge is like barely above 12v? It sometimes takes a while to start the car, so would that affect it? Not sure if i have bad grounds or need a new starter/alt, and it shouldn't be the battery since i got a new one.

Thx again for the tips, I will have a buddy of mine check the solder joints for me.

 

sLEEP,

Check your Alternator for proper output. You could remove it and have an auto parts store test it. You could also drive the car in and they could test it in the car. Alternatively, the FSM covers test procedures for the charging system.

If your Voltmeter indicates 12v while driving then you may have a problem. It may cause the warning lights to dim. Does your CHARGE light stay brightly lit when the others are out? Inspect the V-belts to make sure a) they are tight, but not overtightened, b) they are not loose, c) they are not frayed/chewed up. You may also need to inspect the ground points to ensure they are seated properly and not damaged. If you drive around with a weak alternator then your battery will drain before you know it!

Cheers,
George

 

The only lights that work without fail are the brake and door light. Aside that the other lights(Shift Up as well) sometimes comes on,but most of the times they don't at all. But like i said before, they sometimes come on after driving for awhile, and I put the key on the ON position.

 

sLEEP,

While your friend checks the warning light cluster it is recommended that you verify the grounds to your car, test your alternator, and inspect your v-belts for proper fit and wear. Best of luck on your repairs!

Cheers,
George