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Old 07-26-2002, 10:29 PM
Posts: n/a
300TE Blower Voltages

Hi, I have a 1988 300TE. The blower motor was not working so I took it out and lubed the bearings. It is now working, but it only seems to have one speed. I disconnected the connector and measured the voltages at the yellow and red wire. Red wire to ground was approx battery voltage but the voltage from the yellow wire to ground stayed at approx 7 volts. It did not change when I moved the blower switch from low-med-high. I then measured from the yellow wire to the black wire and it was a constant 1.25 V at all speed settings. Any ideas?
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Old 07-27-2002, 08:06 AM
it leaks, its german
Join Date: Mar 2002
Location: raleigh nc
Posts: 1,111
I dont know the exact voltage relationships but, the small wires to the blower regulator are low voltage control from the fan switch. Should range from 1 to 5 volts, or 3 to 9. The output is from 6 to battery voltage. Whats the amperage draw of the motor? It should be around 20 wide open, more than that and your pushing your luck with regulator and fuse.

Hope this helps,
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.
Raleigh NC
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Old 07-27-2002, 08:26 AM
Registered User
Join Date: Jan 2000
Location: New Bedford, MA USA
Posts: 1,583
The yellow wire provides the control reference voltage from the ACC module. It should vary between 3 to 8 VDC (approximate). Red is system voltage. Black is reference ground for regulator as it is mounted in a plastic housing and the regulator controls the fan speed by varying the amount of conduction in the ground leg of the fan. If I am reading your post correctly, it sounds like your blower had seized and your intervention (lube) freed it up. If this is true, and the fuse did not pop, then you may have damage in the ACC module or possibly the regulator (not likely). If the control voltage as measured on the connector behind the vacuum boost can stays at a constant 7 volts, then the odds are your ACC has been damaged. Check all your fuses and retest the voltages. If no change, then I'm betting ACC module.
Jeff Lawrence
1989 300e
2000 Dodge Grand Caravan SE
No matter what you fix, there will always be something else to fix..
"Warranty" is just another way of postponing the inevitable.
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Old 07-27-2002, 10:38 PM
Posts: n/a
Thanks for the replies. I just checked it again and I'm still getting a constant 7V at the yellow wire irregardless of blower speed position. Also, my fan doesn't run when I press the low fan setting on the ACC. It works when I press the high setting or when on defrost. Is there a way to tell if the ACC is definitely bad. Hate to buy one and not fix the problem.
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