In the engine compartment wiring box there are 2 round 7 pin connectors.
One of those has a connection for the yellow/red wire from the temp
sender to the dash. Unplug that connection and look closely at the pins
for corrosion.

To test, ground the pin with the yellow/red wire, on the side that comes
from the dash, not from the sender. Grounding that pin while the key is
on should make the red led blink immediately and the temp needle rise
quickly. Does it?

Mark

Dan N wrote:
> hi all,
>
> 1991 tintop Syncro coolant temp gauge not moving at all, the red light
> blinks and goes away as usual...it's like this since I bought it ..
>
> - replaced the coolant temp sensor
> - check and redo the coolant temp sensor wire connector
> - check wiring at instrument cluster, blue ribbon looks OK...
>
> I am thinking of getting this coolant gauge replacement at VC (
> http://www.van-cafe.com/temperature-gauge)
>
> what else I have to do or to test the gauge before ordering one? (to make
> sure the one I have is bad)
>
> thanks in advance
>
> dan
>