Gauges change setting when lights go on...??? | 356 Speedster, 550 Spyder, Replica, Automotive Community

craig

My temp gauge and gas gauge needles move significantly when I turn on my headlights. They go toward HIGHER temp and MORE fuel by about 15% of the range in the gauge. I have separate relays on my parking and headlights, but did not do separate HIGH beam - LOW beam relays. Anybody else ever notice this? Would a power drain cause both gauges to to move HIGHER? I would have thought LOWER. Possibly poor ground? Maybe it haunted. I wondered where the ghost in my house has been.

craig

6/7/155:29 PM

Original Post

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Gordon NicholsMassachusetts 1993 CMC Supporting Member

Check the ground on the gauge can and make sure it is making a very positive contact to ground.

Run a separate (dedicated) ground wire if necessary from a known positive ground point on the chassis or frame to the gauge can.

Then, do the same for the +12V feed to the gauge can - make sure the connections are clean and tight.

That should fix it.

6/7/155:45 PM

Robert M

What Gordon said. It seems all/most electrical related issues somehow lead back to a poor ground.

6/7/155:58 PM

craig

Thanks, I'll check connections.

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