EGT Gauge eratic when I put Head lights on???

[PSAJB1]

Like I said EGT gauge eratic when I put Head lights on. Turn off works fine. I should say it happens with the parking lights, which lights all the gauges. The trans and boost are fine. By the way gauges have been in for about 5 years. You can see the gauge jump when I put the lights on, sometimes it will be ok for awhile but then it gets crazy and when I'm at red light in gear it will read 500 soon as I put the lights off it will rest on 400 where it should be. Any ideas are greatly appreciated thanks!!!

 

[TKeeler]

Like I said EGT gauge eratic when I put Head lights on. Turn off works fine. I should say it happens with the parking lights, which lights all the gauges. The trans and boost are fine. By the way gauges have been in for about 5 years. You can see the gauge jump when I put the lights on, sometimes it will be ok for awhile but then it gets crazy and when I'm at red light in gear it will read 500 soon as I put the lights off it will rest on 400 where it should be. Any ideas are greatly appreciated thanks!!!

Are these electric or mechanical gauges? Sounds like they could be electric and you may have an issue with the ground to the gauges or light(s) in the gauge(s). That's what I would check first.

 

[PSAJB1]

Tkeeler

Sorry I didn't state what they were they are autometer phantoms. I'm not sure what they are mechanical or electric. Thanks I will check my grounds!

 

[FordCummins]

Yep, almost guaranteed that a bad ground to the guages is causing the pyrometer to flutter. If the ground from the guages to the chassis checks out, check to make sure none of the ground straps from the body to the frame are messed up. The pyrometer is a pretty sensitive device and needs a good clean ground. If all the grounds check out ok, I would try running a ground wire directly from the pyrometer to the battery (temporarily). If the problem still persists, send the gauge back to Autometer, they will send you another one at no charge, or at least test the one you sent them.