87-93 owners beware?
 

well maybe i am behind in the times or it is just my car, but whenever i put the headlights on, the temperature gauge goes up a little. does anyone else have this problem? or is it just my car? if you never noticed, like me for 2 years owning it, now just noticed, try it and see what happens. :confused:

Mine did that when my battery was running low, for some reason. When I got the 130 amp alternator it went away.

mine does it too. I don't know why though

Never noticed it before but will pay close attention today....

Never happened to me. It doesn't make sense why that would cause the temp to increase. Are there any other factors that may be causing this - anything else you're doing at the time, etc???

It sounds to me like you have a deteriorating ground connection either at the sensor, or the headlights. When you turn the lights on, the grounding available to the sensor is "borrowed" by the lights, affecting the gauge.

Use a jumper wire with aligator clips at both ends, and attach one end to a good ground (pref. the batter post), and the other to the brass base of the temp sensor for the gauge. Start the engine, and turn on your lights and see if it still happens. If it does, then try cleaning the grounds from the headlights. if the problem goes away, or diminishes, you need to R&R the sensor, and clean the threads.

FWIW, a tip I learned in CC that has always been accurate is if you ever have one headlight get really dull, and the other seems a little bright, clean the ground connection for the BRIGHTER of the two headlights. It's got a weak connection, and ends up "borrowing" the ground from the good light, making it dull.

:)

Take care,
~Chris

Could be the instrument panel's voltage regulator.

This used to happen on my 1984 3.8 Mustang, except that ALL the gauges would climb to the max, stick for a few moments, then return to normal... :o

Good luck,

My car has done that for a while also...None of the other gauges change, but the temperature rises about 20 degrees all of sudden :)!!

Thanks,
DoranW

that is what mine is doing. i also noticed you own a 90 as well. i wonder if it has to be with our build date? huh...:confused: