Flickering lights & voltmeter

[masterstream]

All the lights on my '97 CC 4x4 automatic flicker erratically. Headlamps, interior, dash, all of them. No matter whether the engine is hot or cold. The voltmeter quivers in time with the flickering. I had this problem before about 18 months ago. I replaced the PCM and it fixed the problem. The problem came back about 3 months ago, and I have replaced that PCM with a used one and still have the problem. Is it possible that some other electrical device is causing the flickering or causing the PCM to go bad? The local Dodge dealer says they have very little trouble from PCMs and used part suppliers say the ones they have are not in any demand. Thanks.

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[Lil' Dog]

If you have replaced the PCM and it still is bad, check the damper RPM pickup for the PCM. If its fried it'll shut down the charge circuit thinking the engine is shut down.

J-eh

[This message has been edited by Lil' Dog (edited 02-16-2001). ]

 

[illflem]

It sounds like you have a bad ground. Check/clean both ends of the batteries' negative cable.
The problem is more than likely the connection at the block or chassis. I've also had battery cables corrode in the middle,under the insulation,causing a poor connection. Check for this by flexing the cable. The items that draw more current like the starter and headlights will arc across the corrosion and temporarily restore the connection,that's what will cause an intermittent problem.

 

[JJW_ND]

You should check you heater grids for a bad solinoid. You have two solinoids, one for each heater grid. Were the two heavy cables connect to the heaters on the air intake, remove one connection and fasten the wire so it cannot ground. See if removing on of these stops the voltage movement. If it does, that is the bad solinoid. The PCM controls the heater grid, but a bad solinoid will cause the problem.

You could get be with one heater grid down to zero.

jjw
ND

 

[Missouri Mule]

Sorry gentlemen but this sounds(reads) like a Light switch to me.
I will second illflems though. Could be bad ground but more like short.
PCM doesn't control lights. But it does control juice. How much is voltmeter moving?
I think the quiviring if the needle doesn't move up and down at great distances is caused by your lights going on and off especially headlights.
Something to do with the charging could be messed up, such as sensors, relays, wires and connectors or shorting out if you have violent swings of voltmeter.


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Bill Thomas
Missouri Mule - 96 Wht 4X4 ST CC,5 spd, 3. 54, 8 ft bed, 1 ft high cheater boards.
99 Freightliner bl/wht FL60 ISB-5. 9 24v,215 hp,520 tq,6 spd, 3. 59 nsr,16 ft box, 19. 5 tires,Wt/gvw 11,000/23000

[This message has been edited by Missouri Mule (edited 02-17-2001). ]