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Hello, all. This morning I experienced a strange problem with my HVAC. I turned it on to full heat in the automatic setting using the economy vents (floor and side vents). Nothing seemed to happen. I fiddled around with different vents and fan speeds, and finally got it to blow on the high speed setting on the floor/side vents. I switched to a different vent and lost the blower. I hit a few more various buttons but could not get the fan to blow again. I also heard (and have heard periodically) a squeak sounding like a mouse or a cricket coming from what seems like the center of the dash.

Anyone have any ideas? I'm really hoping dash removal will not be necessary. I work for a shop but even at a discount the labor hours required to do that would still add up fast.
 

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You know that the climate control system won't turn on the blower motor until coolant temp reaches a certain value when the fan is in auto mode, right?
 

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Discussion Starter #3
Yes I am aware that the motor does not turn on until coolant temp reaches a specific temperature. It still did not blow today on my way home from work regardless of temperature or having the fan set on high or low. It sounds like something is rattling in the center of the dash a little bit as well. Not sure if it's the blower motor rattling or not, but if it was I suppose it could have shelled itself somehow. Also I noticed tonight that my SRS light blinked on and off a few times, never staying on for more than a few seconds. Not sure if that could be related somehow or not.

Are there any codes that can be pulled related to the HVAC system? I have a home-made blink type code reader I can use if it does.

Of course this all had to happen to day before I was supposed to take it out of town for Thanksgiving... Guess I'll be driving my weekend car for that trip.
 

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Sounds like either the motor or the blower regulator.
Just did the regulator this weekend, not bad, about 3 hours in total.
Unfortunately there is no real way to test without removing.

Here is a link to the removal of both units.

PeachPartsWiki: Blower Motor Removal

The regulator is underneath the motor.

Hope this helps.

Eric S.
 

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I went through the same issue with my 1995 E320. Mine was the blower Motor. Costed me $450 for parts and labor to get it fixed
 

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Discussion Starter #6
Looks like I have enough info to start getting this thing figured out. Of course I'll check to make sure that the motor is actually getting power first. Since I hear the rattle when I turn the system on, it probably is getting power. Thanks for the help, all!
 

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If you start the car and hit the Defrost button, the fan should automatically defect to High and blow air on the windshield. Mine has always done this at least and a good way to test your blower/regulator. I was just recently getting low blower speed....refused to go on High with the Defrost button pushed. It was the regulator....kind of a pain, but since I went through the blower a few yrs ago it was like riding a bicycle....took less than two hrs start to finish. Expect longer for your first rodeo........

If you're repairing/replacing your blower motor, DO replace the regulator, unless you like the idea of going in there again. Conversely, if you're replacing your regulator, check the brushes on your blower motor and oil the end bearings. If your blower motor is just dead, you might want to check the separate fuse strip (30amp) out near the fender well, under the hood (look for pics), before you go any further.

Kevin
 

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Discussion Starter #8
Update... The blower motor worked just fine this morning. IS there still a chance that it's the motor or does this more closely narrow it down to the regulator?
 

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Yes, it's a good chance that the brushes are worn down or the motor bearings are drying out. This would cause intermittent service. Unfortunately, so would a faulty regulator. The difference is usually some 'noise' associated with a faulty blower motor. One test for worn brushes is that when the motor is not working, slam one of the doors and it will usually start again. That won't make any difference if its a regulator.

HOWEVER, if you get it here and just repair one and not attend the other, you will regret it down the road.

Kevin
 

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I'm having similar problems. Could it be the push button unit? I took mine out to trouble shoot and it started working again, but my floor vents don't always work. '88 300E
 

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I'm having similar problems. Could it be the push button unit? I took mine out to trouble shoot and it started working again, but my floor vents don't always work. '88 300E
It can of course be your HVAC panel controls. Bur remember, sporadic signals to the blower motor sometimes motivate the blower motor to work......even if the brushes are worn down. The OP has to replace/rebuild his wiring harness, or he's doomed for other electrical troubles.

Kevin
 

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How can I tell if it's the motor or the regulator?

I'm having a similar problem with my 1992 300CE.
However, in my car there is no air blowing at all, no matter which button is pushed.
Can you tell, from this description, if the problem is the motor or the regulator? And if not, is there a way to test them without taking everything apart? (as in here PeachPartsWiki: Blower Motor Removal ?)
 

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Hope we're not hi-jacking, but check your fuses. The push button control is easy to remove if the fuse is good and tou can check for power there also.
 

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I'm having a similar problem with my 1992 300CE.
However, in my car there is no air blowing at all, no matter which button is pushed.
Can you tell, from this description, if the problem is the motor or the regulator? And if not, is there a way to test them without taking everything apart? (as in here PeachPartsWiki: Blower Motor Removal ?)
You really can't unfortunately....the power goes through the regulator first and then into the blower. You could try taking the regulator pigtail off and checking the terminal that feeds the yellow wire for voltage from your HVAC panel.....but it's really tight in there and I couldn't get my hand in to do anything.

Kevin
 

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Usually its the regulator. To check you can run some wires and put power directly to the motor. Only takes about 30 min to get to it, and if its the blower or the regulator they are right on top of each other so when you figure it out you are right there. Also check the aluminum strip fuse on the drivers side strut tower as it was a silent recall kinda deal to put the external kit in 1992 and older for 124's.

Good Luck.
 

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Usually its the regulator. To check you can run some wires and put power directly to the motor. Only takes about 30 min to get to it, and if its the blower or the regulator they are right on top of each other so when you figure it out you are right there. Also check the aluminum strip fuse on the drivers side strut tower as it was a silent recall kinda deal to put the external kit in 1992 and older for 124's.

Good Luck.
No, you can't power the blower motor directly without access to it. You have to send power through the regulator first....it's how the circuit is wired. The fuse strip was already suggested in the beginning.

Kevin
 

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I said he would have to gain access to test it. If it doesnt say that I will say it now. Fastest way to test is to open up to the motor and put some power to it, by passing the regulator all together. If the blower works that way you just pull it out and replace the regulator. You could spend forever externally troubleshooting and will never find out till you get in there. Doesnt take long.

Good Luck.
 

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You didn't say he had to disassemble a good part of the car to test the motor-that's why I said something. It's also folly to go in there and not do both; re-brush/lube the fan and replace the regulator. Sooner or later the reg will fail if original and more than likely, it will be during horrendous weather circumstances...just because it can.

Kevin
 

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Discussion Starter #19
Update on my original problem:

The blower worked fine for about 4 days, then acted up once. When the motor isn't working, the SRS light will flicker on and off, and this time the ABS light came on and stayed solid. All of the blend doors were opening and closing properly. I drove a short distance, turned off the car, gassed it up, and turned it back on. All the lights were gone and the motor started functioning. This makes me wonder if there is a short somewhere. Any ideas?
 

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Rule out your OVP: make sure it's 100%...even if you have to substitute another. Also, make sure your battery is 100%. These two 'companions' cause a lot of electrical gremlins together.

Kevin
 
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