Hi All:

Can anyone help diagnose a dead A/C blower motor in my 1987 260E. I read through a bunch of threads telling you how to jump the blower motor after you have taken off the blower motor.

Does anyone know how to check to see if the blower motor is getting power or is it the climate controller is broken without taking everything appart?

Your help would be greatly appreciated. It is currently in the mid to high 80's here in Hawaii and 80-95% humidity. Talk about sweating it out. It feels like 100 degrees here. I need a fix quickly.

Aloha,
Eric

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1987 260E Charcoal Grey 157,000 Miles
1987 260E Forest Green 120,000 Miles

Check the fuse -- it's in a small black box on or near the shock mount, inside is an aluminum strip fuse. They crack with age.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Hi Peter:

Thanks for the reply. Sorry I didn't add more to the previous post. I did check all the obvious like fuses and connections. I just need to find out how to check the switch and the motor side.

If anyone knows how to do this, please chime in. I am getting desperate here! Any help would be greatly appreciated!!!

Aloha,
Eric

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1987 260E Charcoal Grey 157,000 Miles
1987 260E Forest Green 120,000 Miles

The blower motor is supplied via a fuse not in the fusebox, it's always powered when the key is on. Speed is controlled by a transistor switching unit inside the blower box via the climate control (I'm not sure what the system is for a manual AC system, I don't believe any were imported into the US).

If the strip fuse is good and you have voltage on the blower side, either the switching unit is bad or the brushes on the blower are bad. To test you must open up the heater box (remove wiper assembly and screen, then unclip the blower cover) and disconnect the switching unit. Ground the brown wire on the blower connector and the blower must come on full speed. If not, and there is voltage on the supply side, the blower is bad (usually worn out brushes). If it does, the switching unit is suspect unless the fuse for the ACC is bad, in which case you won't have a signal to the switching unit.

The yellow wire to the switching unit is the control line, varies from 0 to six V, I think. 6V is full speed.

You must test that strip fuse for continuity, they crack across and LOOK fine, but will fall apart when you remove it.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Just turn on the a/c blower and hook up your VOM...
But.. apparently they only last about 150k depending on use.

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1986 300e (runs like a top.. interior needs parts)
2006 GTO
2003 Mini S

Hi Peter and Zero:

Thank You both for your quick responses. I really appreciate your input.

I was looking for a quick way to diagnose the problem and trying to avoid taking the two to four hours to take the blower motor out and put it back together. I guess there was no other way.

Peter, you were right. The brushes were worn out and I need to replace the blower motor. I have another car that is not running and thought about taking that blower motor but I thought better about it and got a genuine replacement instead since it took a while to break all the stuck screws out. Hopefully this would last another 10 years or so. Paid $325 for the part but I think it would be worth the peace of mind. I hate doing a job twice.

I live near the beach and all the screws and bolts were rusted and stuck big time. It took a lot of penetrating oil, brute force and bloody knuckles to get everything off. I don't want to do this job again!

I am very happy to report that everything is back together and is working fine once again. You all have saved me from getting grief from my wife and son for riding in a hot car and having their hair blow all over with the windows down.

My sincerest Thank You for all your help.

Aloha,
Eric

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1987 260E Charcoal Grey 157,000 Miles
1987 260E Forest Green 120,000 Miles

I think what they were trying to tell you is that a good test-point IS the strip fuse. You can check for power to the motor, you can also disconnect the motor side and test the current consumption of the motor. High amps might mean a seized motor or fan cage, low or no resistance is open circuit brushes.
Gilly

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