I just got a 1990. The light for the speedometer unit flickers. I moved the variable adjustment back and forth several times, but that did not help. Any ideas?

 

The backlight lamps use a flanged socket that bayonets into a hole in the circuit board and makes connection via pads on the circuit board. You have a poor connection from the socket to the board which requires cluster removal and cleaning and/or a new socket.

 

Thank you for your information. I took the car out Sunday for about a 120 mile cruise, and have more symptoms. At first the control unit light was steady. I set cruise control, and about 15 seconds later the ^ shift light came on. The car is an automatic, and I was turning about 2,000 rpm. I turned curise off, but the light did not go out. I hit the brakes and the ^ shift light went out for about 30 seconds, then came back on. I tried several times with cruise on, and each time I hit the brakes the light went out about 30 seconds. Later in the trip the flashing started in the control unit, slow enough that I could still read the speed. The flashing got faster (the MPG area and the MPH area flashed at different speeds), the ^ shift light came on, the light above the rear window defroster would go on and off, and there was a very rapid relay chatter coming from the front/left side of the passenger compartment loud enough that I could hear it at 75-80 mph. Would you think that this originating from the back of the control unit back to the relay, or originating from the relay and going to the control unit? The noise and flashing quit, and I didn't have any more problems, but the ^ shift light did continue to come on. A few times it went out by itself, once or twice it went out when I hit the accelerator, and it always went out when I hit the brake. Other possible factors- I had 3 of 4 high mounted brake lights burnt out. I have replaced them, but have not taken the car out. I can not get the transmission into first with the shifter. I know this is really long, but wanted to be through.
Thank you,
Mike

 

The upshift light operates off the vacuum and normally goes on and off according to engine load. No relays should be chattering when you are driving and you need to find out what relay is involved.