Weird blower motor problem on a Dodge...

[dbp]

Just wondering if anyone has run into anything like this...I'll put some background down at the bottom in case anyone feels like being generous lol.

Anyway, the blower motor in this 09 Dodge Grand Caravan works fine on settings 1, 2, 3...but does NOT work on setting 4 (which is high).

This vehicle does not have Automatic Air, or rear air. The wiring diagram I can get at work shows 5 wires going to the resistor, but there are only 4.

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And here's the info:

Resistor tested ok -- all 4 pins have continuity. Which, according to mitchell, means it is good.

Prong 1 of the resistor has 12.6 volts at all times -- blower motor at 0, 1, 2, 3, and 4.

Apparently the switch controls which resistors the blower motor passes through. On 1, it passes through 3 of the resistors. On 2, it passes through 2 of the resistors. On 3, it passes through 1 of the resistors.

At the blower motor itself, I get 12.6 volts on setting 1, 12.6 on 2, 12.6 on 3, and 0.00 on setting 4.

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Any ideas? And yes, it is a fleet vehicle, out of warranty, so I am stuck with it.

 

[martin]

Any chance you could post up the diagram. It's very strange that it works on the lower settings but not the high one. High usually by-passes the resistor but might have a relay that is not used for the lower settings.

 

[BRUTUS_T_HOG]

they usually wire #4 or "high" straight from the switch.. no need for a resistor when you want full power.

if they don't do that then they use a "high" relay to handle current and not put heat through the switch.

if you share the wiring diagram (assuming it is correct) i can tell you where to look