9 replies to this topic

[humph]

Took my 95 Sidewalk (spi) out earlier for the first time after it's winter storage. Checked all the fluid levels before I set off, all fine. Did about three miles, enough to get the car up to temp, when the aux fan kicked in and wouldn't go off. Every time I started the car it came on with the ignition. Unfortunately I couldn't stick around to see if it carried on doing this once the car cooled down again. At the time the guage was about half way between the blue cold & the white halfway mark, a little lower than it usually does, but certainly wasn't high. 

 

Before I go out and change the switch in the radiator, a pain in the ar$e job when I did it last, is this the likely culprit?  Any other ideas?

[AlexMozza]

Check the wiring first. They can play up sometimes. quite common problem on the MPi's so cpould be a similar issue.

[mk1leg]

I had to replace the sender from stat housing......was not a cheap fix......

[minidizzy]

I had this problem on my MPi about seven years ago. A squirt of WD40 on the themostat sensor connection cured it and it has been fine ever since.

[humph]

Thanks guys. 

 

Plenty of people mentioning thermostat sensor, but don't think from memory I have anything on the thermostat housing. As far as I'm aware mine takes it's signals from the bottom of the radiator, am I wrong?

[minidizzy]

I am not an SPi owner but since no one else has replied I thought this might help to locate the sensor.

From the MiniSpares website:

http://www.minispare...C.aspx?2~20~189

Item 10

Edited by minidizzy, 12 April 2016 - 10:11 AM.

[humph]

Thanks dizzy, I haven't had time to check anything yet but I have wondered if item 10 had any connection to the aux fan, but I don't think it has. That may be wishful thinking as it's a nightmare to get at to change without dismantling a load of bits I don't want to. I'm hoping it's item 22 in this diagram, or rather I'm hoping it's a case of cleaning up terminals.

 

Time to dig out the wiring diagrams

 

http://www.minispare...6.aspx?2~19~180

[Cooperman]

You can simply remove the wires from the thermostatic switch and run them, with suitable extensions, to a switch inside the car and use it as a manually operated fan. IMHO that makes it more reliable and effective.

[humph]

Ok I always like to try and close these threads out with a solution, so here goes. It's another case of, something's broke, take it apart, investigate & find everything fine, put it together and all is ok. Got to the car this morning, first time since I started the thread and as soon as I turned the ignition on the aux fan started, seemed as though it was permanently on with the ignition. Unplugged the relay and drove it home. Relay back in, same again. Took the feed wires to from the fan switch in the radiator off and tested the continuity across the switch, nothing so switched off. Tested the relay for the same, continuity across the control pins, nothing across the switched side. Took a couple of test wires and connected the realy across the battery, could here it clicking and switching. Put the relay and wires back and turned the ignition on, silence  . Took the wires off again and bridged the gap i.e to fake the switch on position and the fan came on as it should. Have run the car for a fair while but the temp doesn't rise unusally and the aux fan doesn't kick in. Still need to test the switch properly with some hot water to rule it out. Coolant needs changing so will do it when I drain the system down in the next few weeks, but so far the fan has at least stopped running.

Edited by humph, 03 May 2016 - 09:16 PM.

[FlyingScot]

Sounds like you have bottomed it. But just in case others find this thread, here are the key points which are muddled in some of the replies...
On SPi the electric fan is controlled by the thermo switch located on the bottom front of the radiator via a tyco (yellow) relay on the bulkhead as you have found. It is held in by a bayonet type fitting and a rubber seal. Wiring as Alex has written can be implicated as it earths at this switch side.

The fan is not controlled by the MEMS ECU and is completely different to the set up on the MPi which is controlled by a temperature sensor and had a service upgrade by Rover when the car was current (the wiring was too short). Item 10 quoted above by mini dizzy is the Engine Coolant Temperature (ECT) sensor which is used by MEMS on the SPi and is also the input which then is used by MEMS to drive the temp gauge.

FS