A Volvo 850 & A Dodge Durango
A Bad Ignition Switch and a Burnt Out Blower Motor Resistor.
Aug 17, 2007
This week explores a 1995 Volvo 850 that may have a bad ignition switch and a 2001 Dodge Durango that only blows on high.
Question: 1995 Volvo 850
Vince:
I have the exact same problem on my 1995 Volvo 850 as reported by an earlier correspondent, (see 1995 Volvo 850). And I read your reply suggesting an ignition switch or wiring problem.
The problem does not occur in the morning at start-up. It manifests itself after the car is driven and parked and restarted. The problem seems to be isolated to the same circuits as described by your earlier correspondent. I, too, thought it might be the ignition switch or electrical connections to that switch. The problem with diagnosis is that the problem is unpredictable and the problem occurs sporadically away from mechanics.
I have not tried smacking the steering wheel but will the next time the problem arises. Was the actual problem actually identified and fixed?
John Byrne
Answer:
Sorry John, but unless the original questioner writes with feedback about the original question, we, at Suite101.com, do not know if the original diagnosis was correct or not. You must keep in mind that without first hand examination of the vehicle in question we, at Suite101.com, can only suggest what the most likely cause of the problem might be and any suggestions should be verified before any repairs are attempted.
Question: 2001 Dodge Durango
Vincent, Appreciate the information you provide for all our problems with our vehicles. We have 2001 Dodge Durango, 4.7 liter V-B, 4x4, loaded. The A/C works on high fan only. It's either a blast of air or nothing. All climate controls are like this. Possibilities??
Thanks…
Answer:
There is a 99.9875% chance you have a burnt out blower motor resistor. Power for the three lower fan speeds go through the blower motor resistor and high speed is a direct feed to the blower motor. So when there is only high speed you have a bad resistor.
The blower motor resistor is mounted to the HVAC unit inside the passenger compartment. It can be accessed from the passenger foot well area. Here is how to replace it...
REMOVAL:
- Disconnect and isolate the battery negative cable.
- From the passenger foot well area, remove the two hex screws used to secure the blower motor resistor.
- Unplug the front blower motor resistor from the wire harness connector.
- Pull the front blower motor resistor and its wire harness out of the plenum panel and through the cowl plenum access hole far enough to access the wire harness connector.
- Remove the front blower motor resistor from the cowl plenum.
INSTALLATION
- Plug the front blower motor resistor into the wire harness connector.
- Install the front blower motor resistor to the HVAC unit. (Orientation required).
- Install and tighten the two screws that secure the HVAC unit. Tighten the mounting screws to 2.2 Nm (20 in. lbs.).
- Connect the battery negative cable.
That’s all for this week. Feel free to browse the archives for past topics. And, as always, if you are stuck and need an immediate answer you can always call Vince on the phone.
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