Ok I am at a bit of a loss. My blower fan only operates on high on my 03 discovery. I replaced the resistor module with a new one from Rock auto, didn't fix it. I ordered a new resistor that I read could fix the old one, soldered it in and it did not fix it. I had a spare head unit I swapped in, that did not fix it. I also installed a new fan motor just because.. Any ideas what else it could be?
I know, fan speed question
- Thread starter Grum.man
- Start date
The fan runs so I know it has power and the F7 fuse is not blown. Is there another one I should check?
I can check for continuity on the ground from the resistor pack to the chassis. Clearly it's getting power from the relay. The other two wires go to the climate control head unit so I can check for continuity there. Any electronic guru know how to test the resister pack?
So new relay and another new resistor didn't fix the issue. At this point I've sunk so much into this that I am just going to live with it.
Ya on my D1 I've had multiple blower switches in it, even took it apart and refreshed them some. Terrible switch! But OP is D2 and electronic switch and said he swapped head units already. So doubtful it's that, unless both head units are bad, rare..
I have a friend that is going to let me borrow theirs that is proven good so that will be my last ditch effort.
I tried an ATC out of a known working Discovery II with no success. The problem I’ve found is that the voltage output from the ATC to the resistor isn’t correct. I don’t recall specific numbers but I compared values on my truck measured at the back of the ATC with the values from a donor at my house. The donor truck ranged from around 2volts to 11 at max. Mine stays around a volt or less until max at which point it’s around 11 volts as well. I’ve got battery voltage to the ATC. I’ve got a good ground from the ATC to the chassis. Any idea what else could cause the ATC to not send out the correct voltage to the resistor pack?
Have you tried the self diagnostics from the ATC? Key on, hold the auto and air distribution buttons down which activates the test for codes. You’ll get 4 beeps when test complete.
Never heard of it. Will the codes be displayed on the head unit? Is there a list of codes somewhere?
I found how to do it online. Have to hold down the buttons while turning the key on. I get error code 21 and 22 which I read can happen if not tested in direct sunlight.