LegalBeast

I am about to pull out whatever hair is left here. I have read lots of forums that start with "I have read all of the forums ... ", but i will be darned if I can find any of them. So, please indulge me on this one ... Here I am minding my own business on my way to the store. AC is working just fine. When I got there, everything was still working just fine. But then when I came out, the blower on the AC would not work. No airflow. There is still cold air coming out, but no blower running. I checked error codes and there are none. I checked fuses and all are OK. I checked for a mechanical problem, but the fan turns freely. So, what else should I be checking. I have looked at a bunch of videos and there are none that have led me anywhere.

So, pardon my being tupid, but what next? Is there a cookbook guide for the 98 R129 SL500? HELP!

ChipThome

Repair manuals like the Haynes or Chilton no longer are published, they've gone online. BUT as far as diagnosing, nothing I have seen so far does it, shy of some of the diagnostic scanners specifically for MB. The generic OBDII won't cut it, so don't waste your money there.

Good luck !!!

bobterry99

If the fuse for the blower motor is good, then it is highly likely that you need a new electronic speed regulator which is often incorrectly referred to as a "resistor". The regulator is mounted on a heat sink attached to the blower motor. This diagnosis would be confirmed by finding control voltage at the connector to the regulator which is located between the brake booster and the windshield. I think all the information you need can be found in the diagnostic manual: http://manual.startekinfo.com/manual..._8/content.jsp.

Brand-new regulators are available on eBay for about $25, but they are not direct replacements, and some work must be done to fit them to the existing heat sink. Someone on Benzworld's R129 forum detailed a procedure in the fall of '16...