Is there a wire in the center instrument cluster harness that powers the coolant temperature warning light?

My aftermarket water temp gauge has a provision for a warning light, and I'd like to connect it to the factory wiring if I can. The VDO senders with warning contacts are really large (1/2" NPT) and could be difficult to mount in the coolant stream. I've been looking for the warning light wire in the Bentley manual wiring diagrams, but I haven't been able to find it.

Also, at what temperature does the factory warning light illuminate?

This is for a 2004 Cooper without navigation.

Thanks for your help.

 

The coolant warning light isn't necessarily wired to a specific power source. It's a surface mounted LED which through the maze of trace on the PCB gets its signal to light whenever the CAN bus messages indicates coolant temp has reached a critical point (240F).

So short answer, there is no way to directly connect the signal input to the warning light to your temp gauge due to that signal is received through a bus message. Your best bet is either through an OBD II signal or directly at the sensor going into the DME.

Test pin #7 at the OBD II connector as that MIGHT be coolant temp signal. Hook up a VDOM to it and see if the values change as you warm up your motor.

 

Thank you for the informative response!

I'm going to see if I can insert the 1/2" NPT VDO sender with the 230 deg. F warning contact in the upper heater hose. I may have to make a "custom" splice piece out of a 1/2" tee and a couple of NPT-to-hose-barb fittings.

 

Sounds like plan. Good luck!