Correct 300e Blower Motor Diagnosis?

Jul 11, 2005 1 Replies
C

Would appreciate what you think of this troubleshooting and diagosis.



'92 300TE w/ 142k miles. Blower Motor totally out - all levels.


  1. Checked voltages at Blower Motor Regulator connector (located above and behind the brake boost)

Yellow = 1v (low fan speed) 4.5v auto 9.5v high Red 12v black Ground


  1. With power to the regulator looking OK, I check the blower motor. Motor is OK

Red = hot (12 v). Blue = not grounded. This is apparently the problem. grounding this lead causes the fan to run very high.


  1. Diagnosis: Blower Relay. My reservation is that I thought the fan would blow constantly on high with a failed Blower Relay.

Thoughts?



Chip L



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T

Wow, got the same problem, but I get no voltage at the Regulator/firewall plug. I even swapped the control panel out with a new one, along with replacing the fan motor and regulator.

I just found that there is a relay??? that controls, among other things, the climate control fan?

i.e. "RELAY

86-9/89 124.030 - up to A 820021 Seat Adjustment Auxiliary Fan Window Regulator Ventilation Control-2-step 10/89-92 124.030 - from A 820022 5-Pins - ALU Casing Ice Cube Increase in Shift Point Burglary Alarm Systems"

I would be interested to know where this is, and if anyone has ever heard of this relay failing for only one of the 5 things it controls, rather than blowing for everything.

Thom

1989 300E, 243,000 mles
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