Hi all,

Recently, I my heat blower motor stopped working when I would press the switch to turn it on. It would come on at times, and then putter out, and eventually stopped turning on at all. Just to make sure it was not faulty wiring, I took it out of the passenger side and connected it directly to my battery (in the same way that you test the starter), with no result. Is this an adequate way to diagnose the death or malfunction of a motor?

Also, I tried the same technique with the 12v auxiliary water/coolant pump, except I connected it directly to the battery without removing it from the coolant circuit, again with no result. I have a second 12v coolant pump (it helps my WVO setup heat up quicker), the newer replacement for the stock one, and have it directly hooked up to the battery with a switch, and it whirls when it is drawing current. Are both the blower motor and the coolant pump toast, or am I testing them inadequately?

Thank you very much,

Bryan

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1984 240D Euro 5 Speed 201,000 miles
1984 300D Euro 4 Speed (runs great but ugly)
1984 300TD 185,000 miles
1985 300TD, 240,000 miles
1972 220D, 240,000 miles w/ a stuck odometer
1984 300D, 214,000 miles
1984 300TD, 255,000 miles rustbucket parts car

Hi Bryan,

It sounds like a good method so long as you are connecting things correctly!

However, if both things are not working isn't it worth testing the battery? (Test for the simple things first!)

The battery's fine, I started the car right up just after testing the components.

__________________
1984 240D Euro 5 Speed 201,000 miles
1984 300D Euro 4 Speed (runs great but ugly)
1984 300TD 185,000 miles
1985 300TD, 240,000 miles
1972 220D, 240,000 miles w/ a stuck odometer
1984 300D, 214,000 miles
1984 300TD, 255,000 miles rustbucket parts car

Hello Bryan,
This is how I test them on client’s cars. You simply place the alligator clamps on the negative side of the battery and the negative side of the pump, and then run the positive wire with the fuse in the middle.

If the pump turns on its good and you have a wiring problem. If it doesn’t you have to replace the pump. This is also a good time to do a coolant flush in the system. Remember every two years flush your coolant out.

But your also right, when the auxiliary pump goes out your wvo takes longer to heat up and sometimes it will not get up to temp at all.
Good luck,

Michael

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Professional greasecar installer
Austin TX


98 Jetta TDI with grease car kit + veg-therm (totaled)
87 MB 300SDL running on B99 / greasecar kit + 30 fphe
www.austingreaseguys.com