Re: [DML] Wacky tach - major issue???

["Derek" <derek.grozio@xxxxxxxxxxx>]

It was during the day and my car has John Herveys relay that only 
turns on the AC panel lights when the headlights are on, so I would 
not have noticed if any of the dash lights had been affected. I do 
have the workshop manual/electrical schematic and have become 
somewhat familiar with reading it recently. I will be cleaning the 
grounds and tracing the wire tonight to try to fix the problem. 
Thanks,

-Derek #10084

--- In dmcnews@xxxxxxxxxxxxxxx, "Elvis Nocita" <elvisnocita@xxxx> 
wrote:
> Derek,
> 
> sounds like an electrical problem so don't worry too much,
> the engine is not going to explode from that ;-)
> 
> 
> Is there any other strange things happening in the dash ?
> Dimm or flickering lights ?
> 
> The Tach has 3 wires. +12V, GND and Signal form the Ignition ECU.
> 
> If the ignition signal would be disturbed, the car would run like
> crap or not at all. I think we can close this out for a second.
> 
> What I would suspect is the GND connection in the center console
> close to the radio. There must be a capacitor near the A/C switch
> and two more from the fan speed switch. The caps are there to filter
> noises from the fan motor that could disturb other systems 
like...the tach ?
> 
> Also - wat does the volt meter show during this situation ?
> 
> May be there is a problem or with the +12V coming from fuse #5.
> At least this is where I would start looking, especialy for loose
> GND connections.
> 
> Do you have a schematic ? Can you read it ?
> 
> Elvis
> 
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