Fried Wires W124
 

The wires that feed my blower motor regulator are fried at the connector on the firewall. The car is a W124. I pulled the blower motor and it works but there is no power to the regulator on any wire. I tested the blower motor out of the car with a battery charger. Itraced back to the connector on the firewall and that connection if fried. Also I don't have cruise control. In all fairness I just purchased this car and the cruise never worked or the blower motor. Any suggestions?

The first thing that comes to mind for me is what was going on at the connector...Logic would say that if you are frying wires there is somehow the wrong fuse in the circuit or you have an internal failure in the blower motor but you say it works. If there is high resistance at the connector because of some kind of corrosion it is possible but not likely the cause of this. I would check the connector itself for defects.
The cruise could have the same problem as most which is bad solder joints in the cruise control amp itself...My cruise in my 123 didn't work at all and I took the cruise amp, opened it up, resoldered every connection on the circuit board, put it back in and it worked fine....

This is a known problem with W124's- I know there was a external fuse kit from the dealer for the fuse box.
Blower motors pull more and more current with age. I bet you need a new blower motor. Repair wiring, new connectors are fairly cheap from the dealer. Make sure you have a external 30 A fuse or cuircuit breaker . What year is your W124?

There is a bunch on this subject if you do a search.

Cruise controls are problematic on benz's. It needs a little trouble shooting, but it could easily be: no brake lights, bad brake light switch, speed actuator, computer, ??speed sensor. Guess the activation switches are fairly reliable=0)



Michael

Fried wires mean heat. Current through resistance is heat. So, there is probably too high resistance (bad connection) in some pin(s) of the connector. Identify the pin(s) and clean or better replace.

Heat in a bad connection causes oxydation, which causes worse connection, leading to more oxydation, etc... a vicious circle.

Once started, difficult to stop. So replace if possible.

I just replaced my blower motor regulator on my w124 93 400e.... I'll be glad to give you the wires from the old blower motor regulator... the wiring is good if you want to splice it before the blow motor regulator resistor attached to the heat sink.