Hello,

Recently, my mechanic told me that I need to replace my 4wd vacuum switch (sits on the passenger side fender). After replacing the switch I drove the truck about an hour. On my way home, I noticed that blower would blow for a few minutes then cycle on an off. I was running the a/c on my drive home.
Could the vacuum switch be faulty and causing this problem?

Thanks

 

Are you sure the blower motor is starting or stopping? Or, is it continuing to run but the air outlet is changing from whatever you've selected to the defrost and back?

Front blower or rear blower? Both or only one?

Do you have the manual or the automatic climate control?

Is your Excursion in fact equipped with four wheel drive?

Details and specifics are vital.

 

There is a real question here: I have had similar issues when on the highway. I have manual climate, put it on A/C and when acceleration to get on the highway or accelerating on the highway above 2200 RPM my dash vents will go to the defrost.
So, vac leak.

I have a 4x4 01 limited.
My old truck that my friend now owns is having the same thing happen
same deal for the build details 01 6.8L

 

Truck is 4wd with auto climate control. The blower isn't working at all now. Today, I reinstalled the old part. Even with the old part, the blower still isn't working. I have not tried the over head switch for the rear blower.

 

The PVH solenoid is not related to the blower motor's electrical operation.

If the blower motor is not operating, it's an electrical issue, whether the motor itself or something in its supply and control circuit.

Good luck.

 

This happened to mine and it turned out to either be a bad connection/pigtail at the blower motor or my motor has a bad connection also. I had to wiggle the wires right at the blower and it's been working fine for 6 months now. I'm pretty sure it's going to crap out on me again just a matter of time. Hope this helps.
Also when I googled this it seemed to be a very common problem.

 

Had something similar happen recently (see another post a few days ago about A/C issues) at about 2000 rpm the front damper would redirect the air past the heater core. At idle the air would be directed correctly. Mechanic had me place the system in manual mode the activate each of the options (air from each of the different vents, a/c an heat from each, recirculate and fresh air from each. After that the system started working just fine whether in manual or automatic mode. Mechanic's hypothesis was that the dampers would either stick in pace or not move fully into position unless regularly (a few times a year). Similar to the 4WD system.

 

After lots of reading and some part swapping. I ordered a new blower control module. As previously stated, removing the bottom screw is a bear. Prices from the stealership ranged from $160.00 - $180.00. Rockauto had it for $61 and it arrived in 2 days.
If you have the three rotary ***** your system uses a resistor to control the blower. If you have the digital readout your system uses the blower control module.


Thanks