Pyro guage acting up

[JWillms]

Intro to what I have:

I have been running Auto Meter Phantom guages seince about mid Oct. and everything has been great(bought them from a friend of mine so not sure how long he had them before I got them). When I instaled them I took my time doing it, I sodered and shrink wraped all the conectoins. For the power to the EGT and transmission I ran the wires from the EGT and transmission into one wire then to the blue wire under the stearing coloum. For the lights I ran all three guages into one wire then into the light switch so they dim and everyihtng.



My problem:

Just the other day my pyro guage would just stop working sometimes at first I just tought it was a random thing and it did it when ever it felt like. Then on Sunday I was driving home and it was about dusk. When I went to turn on my ambers I saw the guage move really fast then go back to where it was, then when I turned on the lights the niddle shook as it slowly worked it way down past 0. Once I saw that I turned on and off my lights a couple of times and got it to do it every time.



My questoin is why would turning on the light have any affect on how the guage acually works seeing how the bulbs are pluged in and completly seperate from the guage. Also if it was a wireing problem wouldnt it also effect my transmission temp that is wired with it, becuse the transmission guage is working flawlessly.



Sorry its so long

Justin<><

 

[SRadke]

A pyrometer measures a millivoltage from the thermocouple in your exhaust manifold. If your lighting system has somehow shorted to feed voltage to the gauge instead of the light it would do wierd things.



-Scott

 

[FJfonda]

1st place to check would be the ground wire.

 

[Philip]

One end of the gage is attached to the engine. It has good ground or the engine will not start. If the body grounds are weak. This would make your gage act up if it was being used as a ground.



So check your body grounds on the truck.

 

[JWillms]

Originally posted by SRadke

A pyrometer measures a millivoltage from the thermocouple in your exhaust manifold. If your lighting system has somehow shorted to feed voltage to the gauge instead of the light it would do wierd things.



-Scott

Well Im pretty sure I got it fixed now. Scott is what your saying that maybe the Pyro wire is runing up againts the wire for the lights and when ever the lights are on its messing with the millivoltage running threw the pyros wire threfor making the pyro act funny when I turn the lights on? If so I took my piller off and found me a nice little wire loom that I ran the pyro wire threw and then hooked everything back up. I also messed with the ground a little just incase that was it. But Im pretty sure the wire loom has taken care of it becuase when I took the piller off the wires looked like they where all braded together.

Thanks for the help guys

Justin<><