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Roger spends his efforts on customer service rather than managing an online catalog. Call Him or e-mail. The fan motors themselves, save the connector, are common to many common European cars of the period. Think Opel, Volvo, Vauxhall, and the like. So the motors themselves are available. Roger will explain the connectors options.
As Stan shares, new genuine Bosch motors would be the ideal relatively permanent solution. You previously shared your preference for finding easier/cheaper things you can make work. The originals "only" lasted 30+ years and nnn,nnn miles. The penalties for overheating are relatively minor, usually cheap and easy stuff like headgaskets and such that you are getting ready to do anyway. Cooling fan controllers and the motors seem like a great place to trim the budget.
Excellent - nice job. I had exactly the same issue, where if I pushed the fan it would start up. I also noticed that it would start from scratch as long as it was in a certain position. Assumed it was a spot on the commutator where the brush was still making contact.
Been following this post with interest. Asking here instead of starting a new post hopefully will help consolidate info in one place. Also have a S4 with both fans not turning on.
Shorted terminals of intake temp switch, bonnet switch in shut position, AC on - none of which activates the fans. Bridging constant 12V from final stage pins 1 and 4 (constant 12V) to fan + turns both fans on. This lead me to believe the ECU/Final stage relay were the culprits so sent both units off to Fix Your Board for repair. Upon return, still no fans!
12V and ground tested OK at both ECU and final stage connectors. Don't have an oscilloscope so unable to test for PWM signal but there's definitely no voltage at pins 5 & 8 of final stage.
Fix Your Board advised the ECU needs to see load from the fans in order to send power. Measuring with multimeter 0.3ohm (00.3 @ 200 ohm setting). Same value for both pins 5 and 8 – both fans same reading.
Hoping you guys can comment whether is is a load/resistance issue @ fans or issue remains with ECU/Final stage. FixYourBoard has offered to re-check but international round trip shipping is quite expensive so wanted to reach out here first. Thanks in advance!
Having just got through a troublesome TB/WP job, doing a test run for an oil leak, temps got a bit high - shorting the sensor (top hose, 98-93C) showed the wiring was OK. Removed the sensor, in a saucepan with thermocouple and DVM, it stayed open circuit with temp showing 102-103, until I moved it around a bit, when it finally closed. Opened reliably at 93C, but without it closing, its useless. This range in the top hose brings fans on just on second mark.
jp 83 Euro S AT 57k
Have you tried shorting the temp sensor that triggers the fans? Simplest things to test are the best starting point. As above, when my fans didnt come on, but worked when shorting the sensor, showed it was the sensor at fault. Also check all and any ground connections in the area. Do you have +12v at both ends of the relevant fuses?
jp 83 Euro S AT 57k
Have you tried shorting the temp sensor that triggers the fans? Simplest things to test are the best starting point. As above, when my fans didnt come on, but worked when shorting the sensor, showed it was the sensor at fault. Also check all and any ground connections in the area. Do you have +12v at both ends of the relevant fuses?
jp 83 Euro S AT 57k
Thanks for your reply. Yes the fans have a good ground and run when supplied 12V at the harness. Both ECU and Final Stage have good ground and power. None of the triggers such as short sensor nor AC gets the fans going.
Seemed to be that problem had to be either the ECU or Final Stage not sending power so sent them in for repair. Have sent them back a second time.
They said the ECU or final stage needs load at fans to trigger them on. Both fans measured, same ohm reading but no data to verify whether the value is in range. Just wondering if any others have found load of fans to be the culprit.
Thanks for your reply. Yes the fans have a good ground and run when supplied 12V at the harness. Both ECU and Final Stage have good ground and power. None of the triggers such as short sensor nor AC gets the fans going.
Seemed to be that problem had to be either the ECU or Final Stage not sending power so sent them in for repair. Have sent them back a second time.
They said the ECU or final stage needs load at fans to trigger them on. Both fans measured, same ohm reading but no data to verify whether the value is in range. Just wondering if any others have found load of fans to be the culprit.
For the fans to run when shorting the inlet switch the engine also has to be above a specific temperature but I do not know what that may be. Maybe it is above the point when the fans are triggered with the ignition on?.
For the fans to run when shorting the inlet switch the engine also has to be above a specific temperature but I do not know what that may be. Maybe it is above the point when the fans are triggered with the ignition on?.
Yes that crossed my mind as well so also tried to short after temps were about 100C.
07-14-2019, 10:09 PM
