aaforever

Heater not working, update from mechanic. please help!
I have a 2003 SL500 and I just got word back from my mechanic. 12 error codes were pulled from the computer. All the codes related to flap motors and it showed that the computer cannot communicate with them. My mechanic told me it may be a wire thats unplugged or cut, because what are the odds of 12 flap motors going bad? right? He recommended that I wait until after the holidays to open up the dash to see if its simply an unplugged cable (from K40 radar detector installation) or a wiring issue. They want me to avoid having any electrical issues on my trip.

Currently my A/C works flawlessly and blow ice cold, but when i try to adjust the temperature to hot, it still blows as if the A/c was on. When i try to change the vents, it does not change, all vents still have cold air coming out of them.

I need to take a long trip next weekend and it would really help to have a heater and my defrosters fully functional while im driving. Can anyone please chime in and let me know what I can do on my side to see if there is anything wrong with the heater cable without having to tear open the dash?

Thanks everyone!

JackStraw

Did your heater work before the K40 installation?

If so, take it back to the installer and have them reconnect the cable.

Don't know where you live, but driving in the icy cold weather without heat or defrost could be a problem.

aaforever

Thanks for the reply.

Actually the problem was there when I bought the car 2 months ago and the k40 was already installed in new York somewhere. I purchased the car in California and it's been raining lately nothing too icy and the defrosters work but just slow because it's using cold air only. I didn't pay much attention to the heater because i bought it when the weather was really hot so that's my fault already.

jonasj92

Having the same issue with my 03 sl500. Did you ever figure out the problem?

aaforever

I was able to fix the problem. I had another mechanic open up the dash. They were able to find an unplugged wire to the dash unit .I'd check there first. Good luck!

jonasj92

Thanks for getting back to me! I know its been almost a decade since you originally posted this but do you happen to remember any specific details regarding the location of the unplugged wire? Do you know if it was on the driver or passenger side? Anything helps!

Thanks,
Jacob