Hello, I am having an issue with my temp gauge. 1985 XJ6 Series 3. No movement when wired normally. When jumpered direct from sender to gauge with key on engine running needle pegs high.
Wondering what the range of the sender is. New sender reads around 640 ohms ambient and 75 ohms when hot.
Any help is appreciated.
Thanks in advance
Dan

 

I had this issue with another old car and couldnt get an answer. In the end I purchased a 200ohm potentiometer (variable resistor) and put it between the gauge and ground and varied the resistance to see what the gauge "liked" Then I had something to go shopping with once I had resistance for gauge min/max and running temp.

Have you earthed the end of the existing temp sender wire (taken off the sender) to see if it pegs the guage. From your description it sounds like the intitial problem may be an open cct or high resistance sender lead. That needs to be clarified before the sender resistance.

 

So after some more research I found that there was a broken wire down by the connector. Once I repaired that I also found that the gauge needs to be grounded to the back of the instrument panel. There is a metal plate behind there that the gauges ground to.