1988 GTA with Digital Dash. Drove the car all day yesterday with no problem. Got in it this morning and the speedometer isn't working and neither is the big screen for the odometer/trip meter etc... I disconnected the battery thinking it would reset the computer and it did nothing. All the fuses are fine. Is the ECM screwed up?

 

Got the speedometer working again but the odometer is still not working. Any ideas would be helpful. Something with the connections Im assuming?

 

hello Joe,

I dont know whats up with your dash but i will try to toss ya a bone bud, I am currently hooking up my 355 i just dropped into a 87 t/a and while i had the engine out , i rehooked the starter wires with a bolt to give me power for my alarm while engine was out (stereo) with it hooked up like this i noticed i had illumination to my digital dash and odometer but no numbers at all,(went to roll up windows) only thing unhooked at present to do this is the grounds , specifically the ones hooked to the backside of the passenger head, and the strap to body. maybe one has loosened for you? as i said i havent a clue but maybe this helps?

 

I'll have to look for some loose grounds. I noticed my power door locks quit working too. There has to be a bad ground somewhere.

 

Figured out that the CTSY fuse was blown. Power locks and dome light is working again. Just need to take the dash apart and reconnect the odometer and see if it works again.

 

Hi:

I can intelligently comment on your issue because I am no stranger to GM cluster issues.

As I type this, i'm looking at the factory shop manual for an 87 Firebird.

The ECM does not have anything to do with cluster operation in this GM car. All the circuitry for the cluster is self contained in the unit, except for the sending units (oil, temp, fuel, etc.).

It is powered by two fuses, the clstr fuse and the ctsy fuse.

How long have you owned this car? I would check the fuses and observe for a while to see if it comes back on prior to any surgery.

It could also be a bad ground connection, although that's unlikely.

The grounds related to the cluster are G112, G118, and G200

G112 and G118 are located at the rear of the R/H cylinder head.
G200 is under the dash to the left of the steering column.

Mostly likely, if it was a bad ground a lot of other circuits that share those grounds would be messed up too.

Bottom line, a common problem with a lot of GM cars from that era is the cluster connections behind the cluster unit. Generally there is a printed circuit board on the back of the cluster that makes a pressed on contact with the connectors on the car. It says here your car has 3 connectors C1, C2, and C3.

In a lot of cases of erratic cluster operation, the connectors on the car need to be cleaned with a pencil eraser and CAREFULLY tightened by bending out the metal tabs to make tighter contact. Then clean the contacts on the circuit board connections with a pencil eraser too.

No guarantees, but hopefully this will help. I really think the 88 is exactly like the 87. I always liked that cluster in those cars....

Lee B.

 

Wow, thats exactly what I needed to hear. I replaced the CTSY fuse this morning. I'll go check the other one as well. Now its only the odometer that isn't working so hopefully the new fuses will help. When I reconnected the odometer yesterday before I found the bad fuse this morning, it would screw the speedometer up. Ive just been driving around today with the odometer disconnected in in the dash.

 

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