My fan doens't work on the highest speed. The fuse is good and I purchases a new A/C fan switch thinking that was the problem. The fan still only works on the first three speeds. I bought the fan switch off of e-bay, so it may be bad also, but is there anything else that could be causing the problem?

John S.
93 850 GLT, manual A/C

 

Chances are the max fan relay is bad. Fans speeds 1-3 run through the resistor pack, the max fan relay bypasses the relay pack altogether when you switch to position 4.

They usually fail the other way around - where speeds 1-3 don't work but 4 works just fine.

...Lee

 

Where is the relay located? under the hood by the fuses or under the dash somewhere?

 

I found the box of relays (right next to the fuses)... but which one is the fan? I switched around the 3 identical square relays and didn't change anything. The relay must be under the hood somewhere. I only have a Haynes manual (not even an owners manual) and it doesn't say what the relays are, just that some are under the hood and some under the dash...

I also didn't find any information on the web. There's a lot of info on fuel pump relays, but not any of the other relays....

 

I would check the fuse first; I could not locate speed-4 relay. The relay in the pic & manual is for the A/C so it may not be the one.


JPN

[IMG]local://upfiles/6892/C100CE8295BD44009782D85FCAF1D003.jpg[/IMG]

[IMG]local://upfiles/6892/E4ADF60B6952413999EAAD02B886F0A2.jpg[/IMG]

[IMG]local://upfiles/6892/F94142603695426DB2F8FFE63EBECAF1.jpg[/IMG]

 

The relay to the left in JPN's picture is the max fan relay. The one to the right is the A/C relay. Be sure to check fuse number 5, it provides power for fan speed number 4 only. Speeds 1-3 are fused via fuse number 31.

...Lee

 

The fuse is definitely good, I even swapped it with a known good one from another circuit....
Thanks for the info on the relay, I'll check it out...

 

Try the blower fan resistor on the passenger side of car under glove box.