Hi guys,

I replaced the leaking expansion tank in my '95 855t last week. It had a small crack at the base of the cap threads and was slowly seeping coolant.

I pulled out the coolant level probe that snaps into the bottom of the tank and popped it into the new one, connected the wiring and filled the tank above the "Min" mark. I didn't find out till the day after that I had not tightened the hose to the bottom of the tank sufficiently (puddle of coolant behind wheel) and found the tank empty. While empty, the low-level light did not come on one the dashboard.

I unplugged the probe's connector and still had no light, so I'll assume an open circuit or high resistance must mean level is ok. Shorting the harness connector's two contacts lit the low level idiot light so that eliminates everything except the probe.

Are they sensitive to being popped in and out of their fittings on the X-tank or maybe require a certain orientation in their mount to have them be triggered by the float in the tank?

I'm prepping the car for my move from Memphis to Roanoke VA and would like to have this circuit working for the 10 hour drive for a little peace of mind. (I'll be more worried about the T-belt I'm putting in this week) Once in VA I'll be in an apartment for a month and won't have the time or a place for car maintenance until we find a house.

Sorry so long,

Thanks,

Erwin in Memphis

Just finished playing with one sensor on a 940 and all the switch does is complete the circuit to ground. Just connect a jumper to ground from one of the wires. Should be the hot and should be a colored wire, not black. With the ign. on the light should come on with the jumper to ground. This would be your starting point and you do not need an empty res. to do it.

dick

The connector that plugs into the probe (switch) has two wires on it. One would be the ground then. I did jumper these two together and the light did come on. This leaves either a probe that stopped working, possibly broke internally, when I pulled it from the old tank and snapped it into the new, OR, the float inside the tank that encircles the probe, is different and won't trigger the switch when the tank is dry.

I haven't experimented with it but suspect the ring-shaped float in the tank is a magnet and it causes the switch to close when it drops low enough around it.

I'll play with it more tomorrow. Maybe by draining the tank and flipping it upside down and back while turning the probe in it's mount I can find the position it needs to be in to work.

Or I could just buy another probe with my next Groton order.

Thanks,

Erwin in Memphis, for now.