I have a problem with the oil temp and CHT gauges. Oil temp sometimes works, sometimes doesn't. When I turn power on, both gauge needles dive to the left. When I disconnect the senders from the gauges, they do the same thing. When I ground the sending units lead (off of the sending unit), they deflect all the way to the right.
Yesterday I disconnected the sensor leads from the back of the gauges with the same results.
I removed the temp bulbs and tested resistance change with a heat gun and they change resistance so I believe they are working.
What shop do you recommend I send the gauges to for repair?