Hi ,
I am having a problem with my sons 1988 300E with 110,000 miles. The blower motor wont turn on. I have used the search function and checked all the fuses etc. I have no 12V at the external fuse at all on either side of the fuse. The wires appear to go into the firewall. I have also read that the power for this fuse is wired in parallel from the #12 fuse in the fuse box. I replaced a ignition switch a few months ago to fix a no start problem. I checked the wires on the switch to make sure none popped of the terminals. I also verified that 12V is present at terminals 15 and 15R. Does the 12volts for the blower fuse go thru the ignition switch or direct from the battery. Its getting cold and i want my son to be safe with good defrost etc any help would be appreciated.

SDT

Hi there,

The diagram I have shows external fuse F15 is powered directly by S2/1 of the ignition switch. Please double check S2/1 terminal. The wire colour here is sw/gn.

From the external fuse F15 it goes to a 3 pole connector X34 in the engine compartment above the brake booster at the firewall. From this connector three wires go to the blower/regulator. Some early models had the external fuse fitted after production so it could be slightly different.

power, ground, and control voltage from the pushbutton assembly should be present at the connector side of X64 with the wire harness unpluged, ignition on, blower on.
Your problem is likely the wire from ignition sw.
Good luck,
Acky

Hi Uncle Acky

My ignition switch does not have that terminal designation. I have 15,15R
15X,30,P30,and 50. Actually the blower worked after the switch was replaced for a while but now nothing.

SDT

is it a 124.083 or what? also is it automatic or manual trans?

I'll double check the diagrams...there are several for quite a number of models.
Thanks,
Acky

Hi again,

Please let me know re: eng 124..... and trans.

I see starting 1988 no connection to F12.

Wired directly from X15 at ignition sw, wire colour pk/gn. Powered in run, ignition ON.

Acky

Hey SDT,

I see you have a 124.030 and likley auto trans, correct?
Send me an e-mail and I will reply with diagram. The bad news is that it too shows power from ignition switch to F15 to X64 to blower regulator N29 to blower motor M2.
Acky