Ignition Interfernce with Dash Cluster and Radio Problem

[jfmenden@aol.com]

I have an 84, the RPM side of the dash cluster flashes, and the radio has ignition static. I have had it in the dealer 3 times, they charged me 500 to rebuild the dash cluster, did not fix, then said it was normal when cold, then said there was a short on the engine ground, still did not fix. I am pulling my hair out here. Have new wires, plugs, cap and rotor. I am pretty sure it is an ignition problem as it is only on the RPM side, and in the radio. Also, when I hit the brakes, has a loud popping sound through the radio coming from one of the brake switches. Any ideas what to check? Is there a noise suppression device on the car? Or some other ground spot I should check? Hate to spend more money taking it to the local corvette shop. Any help would be appreciated.
One more thing, the left side hood light blinks when running. Something is definitely going on with the ground circuit I think.

Does anyone know if the Tach Filter could have anything to do with it? Also, the wire that comes out of the distributor and goes to the tach filter before going to the tach has an extra wire hanging out? Is this for an external Tach or should something be attached. I can't find anything in the schematics

 

[Robertwav1]

I would check out the Alternator. I once had a problem with dash lights pulsating and that's what it was. I'm not saying that's the problem but it's something to check. Odd it's only one side of the dash, but, discreet devices can do some weird things. Maybe you could borrow one, pop it in and see if it makes any difference. By all means figure it out yourself...you will find it!

 

[jfmenden@aol.com]

Continued Saga

Well I tore the car apart today and checked all wires, grounds, connections, unplugged components etc. I even disconnected the alternator and ran straight off of battery power. Then I happened to notice that when I turned my blinker on the cluster quit flashing. So, back to work on the internet I go. I found an article that stated if you loose your ground between the circuit boards in the cluster, you will notice that when you operate your blinkers or high beam, the cluster will use that circuit to complete the ground. So, back to the dealer she goes for the 4th time, and they will get told to pull the cluster again and send it back.

 

[Ken]

It wouldn't be the first time a part was defective from the factory. I had a brand new computer in mine that was bad from the start last year.

 

[geekinavette]

The problem may not be in the cluster at all. There are three ground points that need to be checked out:

On the passenger's side door hinge pillar (there should be two ground wires here, one for the radio and one for the cluster)

On the rear of the driver's side cylinder head (two here also)

On the trans bell housing on the driver's side

Bill

 

[Robertwav1]

Nice prints there G..... That would be a good start!