Fan help

[Leon_1.8T]

Right guys, my fans haven't been working so done a bit of simple testing, there is power to the fan switch on rad and when bridging to one of the output both fans come on at low speed but nothing on the other output.. I'm going to replace the fan switch for a genuine part but what could be causing the other output (I'm guessing full speed) to do nothing?

 

[cleverspoon]

You need to bridge the full speed connection then turn ignition on for them to work.

 

[Leon_1.8T]

Ok I'll try that.. Where does the wire go to from that connection? It seems to have stopped working even in bridging I slow connector but still power to the connector.. Thanks in advance

 

[cleverspoon]

Theres a control module under the battery some where which cobtrols the ac comp and fans. The easiest test is to turn on air con and see if the slow speed fans run, they should both run in slow speed. If they dont run in slow speed but pulse on and off on high speed (noisy) then more than likely the slow speed resistors have burnt out.
You can also test slow speed by bridging the thermo switch on rad, theres a guide on youtube. High speed will only work with ignition on.

The easiest test is with the air con, set temp to low with ac on and make sure its blowing cold, then observe fans.

 

[Leon_1.8T]

Thank you so much for your help so far.. I did the test with air con the other day and fans done nothing but bridging power to slow speed did work until this morning - the bridging wire got very warn though.. Bridging power to fast speed with ignition on does work.. So possibly fan switch and unit under battery both gone?

 

[cleverspoon]

If ac is running (cold air blowing out) the fans should run on slow speed, after 30 sec to 1 min (maybe a bit longer) the fans should come on high speed as the condensing pressures will rise. If slow speed doesnt run its more than likely burnt out resistors (very common), but could possibly be fan control module (not very common).
If you look ip the fan fix on here (slow speed fan fix or something like that) theres a wirring diagram and explanation on the repair. I used that and tested the resistance of my slow speed windings and it was open circuit, indicating burnt out resistors, did the resistor mod (cost £15 for resistors and a few hours of my time) all running as should.

95% of the time it will be burnt out resistors, but could be the control module or radiator thermo switch, also check the fuses on top of the battery. The easiest check is ac on, confirm its on by cold air coming out of grilles, wait a few min and the high speed fans should come on to maintain condensing pressure. If nothing happens then further investigation will be req, but you have proved high speed by linking thermoswitch, so my moneys on burnt out resistors