A/C Fan problem - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Jesmol · 01-27-2002, 14:43

Does anybody know what would cause the A/C fan not to work in the "3" setting, it works fine at every other speed, I have taken the switch apart and cannot find anything wrong with it, Anybody got any other clues?

botch · 01-27-2002, 15:07

can cause this, they are located behind the glovebox and have 2 screws holding them into the heater/evap box between the heater fan and evaperator. You may have to move the main loom to ecu out ot the road to access this. you can also check your switch by unplugging the fan resistors and probing into the plug. There should be power getting to one wire per fan switch setting.

01-27-2002, 23:39

Had same problem with my au took it back to ford said it was a loose wire fixed it in 3 hours though

Jesmol · 01-28-2002, 01:09

Quote:

Originally posted by botch
can cause this, they are located behind the glovebox and have 2 screws holding them into the heater/evap box between the heater fan and evaperator. You may have to move the main loom to ecu out ot the road to access this. you can also check your switch by unplugging the fan resistors and probing into the plug. There should be power getting to one wire per fan switch setting.

Thanks Botch, tried this but it hasn't worked, I have checked the switch like you said, and I get the 12 v through one per fan setting, but when the fan setting is on three, the voltage going through the only resistor is about 1v , whereas all the other run up to 3 volts depending upon fan setting.
Resistors all look OK, and continuity check all work OK, what is a little wierd is that everynow and again the fan will work on three, and after about 2s it slows right down (not a sudden switch off, but a wind down ?)
There is some corrision on the resistor joints, is it worth soldering these?

Jesmol · 01-28-2002, 02:16

Now I'm just getting confused. I checked for the single voltage per wire, and got 12v on the Yellow with blue trace wire, for fan setting 3, this is without the resistor fitted, but when I connect it to the resistor block, and re-check the voltage, it drop down to 0.3 volts, this is checking before the resistor, so I am assuming I should still get 12v.
I did this check several times, and have even tried checking from the back of the plug, it's still the same, ie get 12v before hooking up connector, then get 0.3 after connector fitted. Doesn't make any sense to me?

Jesmol · 01-28-2002, 23:42

All fixed, replaced fan switch (do you think the local Ford Dealer could find the part on the spares list, took 3 of them 1/2 an hour, finally found it under Heater boost switch low (?)), and problem gone, can only think it must have been a bit of crap built up in the switch contacts.
Bloody AUto Electrics, might as well be black magic!

Donut King · 01-28-2002, 23:45

I have the problem that my a/c fan on the XF only works on the highest setting and not in the low settings, any idea on what the problem could be here? :s2:

Jesmol · 01-29-2002, 00:04

Quote:

Originally posted by DONUT KING
I have the problem that my a/c fan on the XF only works on the highest setting and not in the low settings, any idea on what the problem could be here? :s2:

Based on what I took apart it could either be the switch or the resistor block part numbers for these are XF19986A (Switch Htr Bstr Low) and EA18591A (resistor) , the correct one for an XF maybe a slightly different number but the 18591A is the important part.
If the fan is only working on High then my initial guess would be the resistor, which as Botch said can be taken out by removing the glovebox, and locating the block with four wires going into it in it , and remove the wiring, undo the screws, and remove the whole block. On an XF I think there is an A/C thermostat in the way (made from galv steel I think), and the resistors should be behind that. I found it easier to test the unit by plugging it back in to the harness where in free air, but the resistors need fresh air to cool them down so dont run for too long.

botch · 01-29-2002, 02:12

hey jesmol, with a reply like that to dk, i think your overqualifed to be an auto elec.

Well done mate!

01-29-2002, 02:49

My AU ute goes back to dealer for this very soon. The best part is when I switch it to 3 it works fine until I change gears, then it drops back to the same flow as setting 1.