HELP, I Live in the south and I have to AIR....

[epwman]

I have a 1994 E420. The blower motor went bad, common, then the regulator, common, I fixed both. The system was working fine. My acutators are bad so I didnt have air except on the side vents and the defrost vents. So I forced the center vents to open and poped off the control arm to have center air/heat at all times. Then the blower quit, came on again and quit again then stopped completely. I thought it was the regulator again so I replaced it, no luck. I put power directly to the blower and it works fine. There seems to be no power coming to the regulator from inside the car. I put a voltage tester to the regulator, the yellow wire has power the red does not.

HELP>>>> I live in the south, it is 97 degrees and humid, I work in a business suit I have to have air.

[Arthur Dalton]

Link fuse F15 is bad.

Near Left shock tower.

*R/L correction.................

[Ferdman]

Arthur, don't you mean the 30-amp strip fuse near the left (driver's side) shock tower? Loosen the 2 screws securing the 30-amp and examine it for a hairline crack across the center. A replacement costs less than $2.

[epwman]

You were right the fuse on the drivers side was blown. I touched the two connections together and the blower came on. Thanks guys.

[Arthur Dalton]

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Yeah---Typo..
Drivers side .. fuse F15/30 Amp.

That is feed from Ign sw to reg/motor. Alway check those links before changing reg/motor .......very common fault.

[epwman]

The fuse was blown, like you guys said near the drivers side shock tower. I replaced it today and the blower works, ac works. I had to buy a fuse at NAPA, they didnt have one like I needed so I bought a 50AMP fuse with screw holes close enough to fit.

Now comes the new problem. I put everything back together. AC still works blower still works only now the dam thing will not go on low or off. It is stuck on HIGH....It works for me now, I needed air, but I just want it right. What do you thiink it is? It will not turn off, or low, or work on automatic, all it does is blow on high.

Help!!

[Arthur Dalton]

The correct diagnosis for fan circuit is a simple voltage test at the 3 wire connector behind the brake booster. [ on the firewall]
That is where you should have gone way before changing the blower and regulator. It is a simple 30 sec test that will test both the fan power feed and the CP output for the Regulator circuit. Don't go down to blower and stuff until you do the test up top. Specially on that chassis,,,
Three prong plug ...Red/Blk/Yl
Red + to Blk - , 12V
Yellow to Black , variable V. , 2-9 v , depending on the settin the CC panel.
Key ON.
If both test PASS , the problem is the reg..if Variable V does not, the CP is the problem.
You may want to use the Search Feature we have here on top of the page..all these primary test are explained in detail there several times over...and they will save you time and $$$$.

....and the Last thing you want on that Reg/Blower circuit is to protect it [ or should I say Not protect it ] with a 50 AMP fuse.....

[Ferdman]

epwman, as Arthur recommends replace that 50-amp fuse with the correct 30-amp fuse ASAP before you burn up a CC component or start a fire in your E420. Your local MB dealer should have 30-amp strip fuses in stock, if not the dealer can get them overnight.

[epwman]

Tested the three prong plug. Yellow to ground put out about 9V. But could not get RED to black to do anything except try to pull the needle to the negative side. Since the blower is blowing full speed I assume the red is working but I could get no reading.

What do you think? The Control Panel?

[epwman]

I will change it as soon as possible. Will Disconnect in the mean time. Thanks.

[Arthur Dalton]

If you are getting a neg reading on red/blk, you have the polarity wrong on your meter.

Try red to ground....

[epwman]

I tried red to ground and everything in between, only once I got a little spike in the needle but it went away. Do you think I might have switched the two connections on the Control panel with each other?

[Arthur Dalton]

I sdid not know you got into the CP too...

Why are you giving me yl to ground readings ????? ..I asked for yl to blk.

[epwman]

Cant get any reading at all on black to yellow or black to red. Red will not ground either, yellow does ground. Tested tester and it is working right.

Suggestions?

[Arthur Dalton]

What does that mean????