V6 Circulation pum/cooling fan switch part

[Adrian]

Me again (after such a long break I just had to re-register!).

Anyway, my Calibra V6 still going strong but the cooling system is running on way too long after switching the engine off. So using the Haynes wiring diagram I think I've traced it down to S29 (located on the coolant bridge I think) but after half a day's googling I'm still not sure what part number this is to order. The ECU has a sensor, the temp. gauge has a sensor, the Main Fan has a sensor (switch) but all the parts catalogues I've looked at online don't help to distinguish between them. Often they call a switch a sensor which doesn't help. Any pointers to the GM code?

[v6 steve]

im 90% sure its the sensor on the bridge that turns the run on on/off

[Fraz]

That is the ecu temp sensor ...the one you want is this one I think

http://www.ebay.co.uk/itm/Genuine-Vauxh ... 0869301364

[Adrian]

<Choke> £40?

Thanks anyway, there are quite a few temperature sensors/switches so I've done a survey of all related parts in case it's a help to anyone else. Partsbase #21 shows the one you pointed to Fraz (90462372). The most useful thing is having it described as either a sensor or a switch. (Link to Partsbase)

Also, I know for sure it isn't 28C outside right now so my ambient sensor is up the creek as well so I added that to the collection. Now I'm wondering about the other sensors feeding the ECU.

[Adrian]

In case it's any use to anyone, to keep all the info together, I'm continuing the story in this thread even though it's been a while...

So I found that the problem wasn't the temperature-sensitive switch that turns on the fan and aux. circulating pump. It was the pump that had seized. That was handy because I managed to clean the impeller and got it going again (rather than shell out £100+ for a new one).

Just recently, however, the fan came on and stayed on until I pulled the green relay in the engine bay relay box. This time the thermostatic switch (Haynes S29) really has gone bad. So I googled around for a replacement and found it costs around £30

Now call me tight but no matter how fancy the housing, that's plain silly for a bi-metal switch. Given that this is there to circulate coolant and blow air through the radiator/over the alternator after a hot engine is turned off, I've knocked-up a timer with some old-school logic gates that switch on the relay (Haynes K27) for a few minutes every time the ignition is turned off. All the wires are just pushed into the relay bases but it works a treat

The white relay (Haynes K22) has a handy tap point for the ignition on terminal 86 and ground on terminal 85 while the green relay (Haynes K27) has constant 12V on terminal 86 and grounding terminal 85 with the timer (S29 Disconnected) does the job.

[Adrian]

The only problem I can see is that it won't run the alternator cooling fan if the block gets hot with the engine running. I don't know if this is a realistic situation given that the main electric fan should keep temperatures in check. Wish I'd wired a LED on that circuit before (often wondered about it!).

[EddeyDancer]

Do you have a Listing of what them relays and fuses are, and for their functions?