93 sl2 heater gauge problem
 

Hello
when idling, the gauge has been rising to and even a bit past 3/4 at night but when i turn down the headlights to parking lights or turn off lights altogether it returns to normal .. at halfway.
any ideas on why this ??

is the cooling fan kicking on before the needle starts to drop?

I'd check the instrument panel grounding splice pack -- sounds like a loose connection in your temp gauge grounding circuit

derf: i don't think so but the drop is instaneous when i dim the headlights from just past 3/4 down to 1/2 i dont think the fan makes it happen

ocean archer: thanks very much that seems likely i'll google the temp gauge grounding circuit and see if i can locate it lol i have a good & trusty mechanic but he's expensive !!

based on your response, I'm with OA that it is an electrical issue. Does anything else on the dash or elsewhere act up?

Remember -- 93's had two temp sensors -- one that drives the gauge and one that feeds into the PCM. So your dash can act goofy independent of the actual temp info being read by the PCM -- thus not influencing the operation of the vehicle......

Have you tried reading the battery voltage with headlights on vs just parking lights? It'd be nice to rule out charging system problems before going after the cluster

thank you i am greatly relieved that it might be my gauge acting goofy and not my car trying to overheat lol same thing happens when i turn off lights completely as when i go one step down to parking lights. thank you for the peace of mind you've given me. when i get the money i'll have my mechanic check the electric but in the meantime i'll stop freaking out. love, zigi

I have to go along with all of the above. All in part based on the year of your car, one of the early ones with the two temperature sensors. It might pay to just check the fuses to see to it they are seated properly. (1) they have been known to vibrate loose and when that happens the contact is iffy, just pulling it and re-seating them is adequate. The ones related to dashboard or interior lighting are probably the ones of concern.
(2) That was a problem with mine and I have since heard of more of them. And usually with in the first couple of years of manufacturing. Mine is a 94