Temperature Gauge False Alarm-gctid394805

[Guest]

I have a very strange problem. I have two batteries with a standard Perko battery selector switch. The switch was installed two years ago and I haven't had any problems until now. Battery two is connected in the normal fashion: The negative cable goes straight to the engine, and the Positive cable goes to Post 2 of the switch. Nothing else is connected directly to battery 2.

Here is the problem: With the engine off, I turn the battery switch to position 2. The temperature gauge immediately jumps up, like the engine is running. If I turn on any accessory (blower, radio, nav lights), the temp gauge jumps up/right and the high temperature alarm starts sounding.

Everything works. If I start the engine, the alarm goes off and the temperature gauge shows the normal temperature.

With the battery switch in position 1 or Both, everything is fine. I have tried switching the batteries, and the problem still occurs, so the problem definitely seems related to the switch.

Anybody have any ideas? Has anyone seen this before?

[Guest]

did you check the connections on the rear of the switch? Sounds to me like a high contact resistance and these nuts can come lose. It could also be the cable to eye connection slowly rotting away.

As I think about it: it could also be the ground cable being lose or corroded.

[Guest]

Thanks for the reply. The negative-to-ground connection is fine. I'll take the switch off the wall and see if there is a problem back there.