Hi all, returning after long hiatus. Finally got my Niece's MPI Schumacher Sei to my house to work on. I'm currently investigating and removing the utter bodge-up of the fan wiring. The wiring from the radiator thermo-switch has been entirely removed and directly wired to the fan and an un-fused 12V feed was supplied from the cabin via a pull switch. Yes, it seems to have been slightly on fire at some point in its past. Questions/observations:
1. What is the relationship between the radiator thermo-switch and the ECU, and the temperature sensor on the head and the ECU? i.e. why is the rad-switch even needed if the ECU references the temperature sensor? It may be that there has been a non-original rad. fitted to my car - nothing would surprise me at this point.
2. Once all the splices/Scotchloks The system appears to be factory wired as per the attached diagram (Yes, I know I draw like a drunk child). The MPI seems to have a constant ground to the fan and a switched 12 V, which is apparently supplied via the ECU actuating the relay. I have verified the continuity on the connections shown. As far as I can see, it agrees with what Honeymonster's findings in this thread.
3. The fan operates when powered directly.
4. The rad-swich wiring is entirely missing. I got (what I thought) was the loom section from the scrappies which has the rad-switch, and it is wired in with the horn on that example. On my car, the horn arrives in a plastic carrier on its own. I have looked inside the upstream loom branches and there is no remnant which I can find.
Assuming the MPI ECU references the head temp. sensor alone to actuate the fan, and the rad. switch is an artefact of having a non-standard rad fitted the wiring is now correct - is there anything I'm missing?
Alternatively, if the rad-switch is also needed, can someone please tell me, preferably with the aid of a photo, where the rad-switch wiring goes.
Many thanks in advance for any assistance.
1. What is the relationship between the radiator thermo-switch and the ECU, and the temperature sensor on the head and the ECU? i.e. why is the rad-switch even needed if the ECU references the temperature sensor? It may be that there has been a non-original rad. fitted to my car - nothing would surprise me at this point.
2. Once all the splices/Scotchloks The system appears to be factory wired as per the attached diagram (Yes, I know I draw like a drunk child). The MPI seems to have a constant ground to the fan and a switched 12 V, which is apparently supplied via the ECU actuating the relay. I have verified the continuity on the connections shown. As far as I can see, it agrees with what Honeymonster's findings in this thread.
3. The fan operates when powered directly.
4. The rad-swich wiring is entirely missing. I got (what I thought) was the loom section from the scrappies which has the rad-switch, and it is wired in with the horn on that example. On my car, the horn arrives in a plastic carrier on its own. I have looked inside the upstream loom branches and there is no remnant which I can find.
Assuming the MPI ECU references the head temp. sensor alone to actuate the fan, and the rad. switch is an artefact of having a non-standard rad fitted the wiring is now correct - is there anything I'm missing?
Alternatively, if the rad-switch is also needed, can someone please tell me, preferably with the aid of a photo, where the rad-switch wiring goes.
Many thanks in advance for any assistance.
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