wynryder

I have a 99 SC400 that I bought a year and a half ago, love the car but the heater/ac fan will only blow on low speed 99% of the time and will randomly go to the indicated speed on the controller every once in a while. I have tried replacing the variable resistor with no help, I thought I would post here and see if anybody can help on this issue.

scENFORCER

U sure its not in 'auto' mode or something?

I'd say the easiest way to deal with this is to source a new (used) unit from one of the vendors on here. Try PM'ing user 'aliga', he sells used SC parts on here. You should be able to get it for like $100.
I know the '99 units are a bit different from the older ones, so I'd be sure to replace it with another '99 unit (unless you can confirm that 98-00 units are all the same, but I doubt older than 98 units will work).

SpadedOne

iTrader: (1)

I have almost the same problem. 98 SC3. Mines is on full speed most of the time. Fades to the actual setting every once in a while. I was going to do the resistor myself, but couldn't verify that would fix it. I've checked most of the grounding wires throughout the whole car, that's not the problem. I've only found one post on here talking about the same thing. The problems were on earlier models that had a different system than us. They suggested replacing the whole fan unit as well, but no confirmation on if it worked or not. I too am thinking the whole fan unit needs to be replaced. If you go that route, please come back with the results for future reference.

Sc400NL

as i know from my previous car and that of my wife (Honda) , its the resistor when the fan only blows at high speed , the low speed issue i don't know