Electrical gremlins! Wife's driving, help!

My wife is on her way home with another 45 minutes of her 90 minute commute. She just called and said that the temp gauge was jumping from "very low" to 150° normally runs at 200-210. I had her pull into a rest stop and take a look. Everything looked good so I'm thinking bad sender or gauge, I'll check it in the AM. She just called and said that she was intermittently losing the headlights. 1999 AX15 any ideas?

Definitely electrical, no way the temps are really changing that way. I'd suspect a really bad lose ground somewhere, like near the battery if the headlights are also in it. If the engine isn't faltering though...

Have you ever replaced the battery cables?

I had OEM cables on my '98 that was giving me all sorts of electrical problems. The terminal clamps/connection looked fine, but it turns out the cable had corroded away to almost dust inside the insulation. You couldn't visually see anything wrong.

If nothing more, the battery cables should be replaced on your '99 if they haven't already.

On many models, there is a circuit breaker built-into the headlight switch. If they turn off and come back fairly rhythmically it is likely you have a power overdraw in the system. Have you installed non-standard headlights? The next best guess would be corrosion on a connector, either at the headlight plug or the connector behind the air box

Thanks for the input gents! Last night when she got home, the temperature gauge was back to normal. However, the high beams wouldn't come on when switching normally. They did work with the flash to pass mode and the switch being held back. I replaced the multifunction switch last year and everything available was of course manufactured in China. I thinking that the switch is failing, which would explain the headlight problem. Does the temperature gauge power run through the switch? Could it be as simple as that? I'll check the cables and grounds, but they aren't too old and I'm pretty diligent about keeping electrics in good shape. As a side note, I really hate that getting quality parts is getting so difficult. The original starter died after 10-12 years of use, I'd get a year at best from the best I could get from what was in stock locally. Eventually, I was proactive enough to pull a starter from the salvage yard and had it rebuilt by a local auto electric shop to a higher standard. It didn't cost much more than the "lifetime guarantee" rebuilt junk available from the auto parts store and it's much stronger and hasn't let me down in years...

Can anyone confirm weather or not the temperature gauge circuit is in any way connected to the multifunction switch circuit. I've inspected everything and the only thing that's seems out of sorts is the switch. Thanks for your help!

On my 98 the temp gauge will some times drop out, even after coming up to temp. The fix has been to just un plug it and plug it back Its in a bad place for spray and temp swings

As far as the connection between the temp gauge and the multi position switch,12Volts,,,,,,check the battery connection.

Wayne Sihler said:

On my 98 the temp gauge will some times drop out, even after coming up to temp. The fix has been to just un plug it and plug it back Its in a bad place for spray and temp swings

As far as the connection between the temp gauge and the multi position switch,12Volts,,,,,,check the battery connection.

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Thanks for your help!
Maybe I'm dense, but I'm not sure what you are trying to tell me in regards to the connection between the gauge and switch...

saburai said:

Thanks for your help!
Maybe I'm dense, but I'm not sure what you are trying to tell me in regards to the connection between the gauge and switch...

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There is none.