[pdg]

Have the book symbol. Dash off and blend motors bench tested - both work smoothly
Distribution servo working ok
Recirculation servos working ok. (had to replace the white gear drivers side- US version)

Did a complete dash removal including the metal brackets supporting the recirculation boxes. (4 bolts located on the fire wall inside the air intake plenum

Did not have to remove the steering column

Testing problems:
Having USB/win7 run time errors when attempting to communicate with my MSV black box
Having widows xp issues with my Panasonic tough book - cannot launch web browser ( must be a virus)
Having issues with the xp rebuild disc I purchased from e-bay
So electronic testing at a stand still at the moment. Pending purchase of are placement tough book.

1- My question is are the blend motors inoperable via the HVAC control unit until the error codes are clear.
2- anxious to rebuild the dash prior MSV code clearing and testing. As I feel confident that the actual blend motors are ok.

 

[tompage81]

I also tackled the driverside blend motor today (the single one just to the right of the steering colum) as I had been getting no cold air out of the drivers side vents for a week or so before my rig went into the shop.
Have previously replaced both of the blower motor blend motors and upon inspection of these (quite a while ago) there were stripped cogs in both but when I removed the blend motor today there were no stripped cogs at all and it seemed to be in good condition.
Now as of right now my engine is stripped down to the bare block so I have no real way of testing this and seen as I went to quite a bit of hassle stripping out half my truck to get to it I'm wondering if theres a way I can test these 3 centre consol blend motors before I actually get my motor & battery back in the truck?

 

[SteveG]

Tom, could you possibly hook up a battery jump pack or charger that will provide a constant voltage right to the wires? Never done it on a electrical finicky p38 but I have done it on other cars...

 

[leftlanetruckin]

Run Vehicle Explorer in compatibility mode for Win XP.
Run VE as "administrator" at all times.
Doing that, I have never had a runtime 75 error when using Vista or Win7.
Also, when you plug the Faultmate into the USB port, open My Computer and make sure the computer is seeing that the port is in use. I had to download the Prolific drivers on a couple of Win7 laptops.

Martin

 

[Jos Geuze]

Hi

Blend motors have feedback signal from potentiometer back to the ecu. If these fail the ecu does not have feedback at what position the blend motors are. See the link below for repair details:

http://www.stockholmviews.com/p38/index.html#blend

Regards

Jos

 

[marty_nz]

You could also unplug the connector for the blend motors from the HEVAC ECU and just use a smaller 12V battery, or power source to jumper the wires to move the motors manually. I think a 9V battery will work actually...

You will just need to be careful, as the motor will stall when it gets to the end of it's travel, which if you don't remove the power quickly could damage the motor/gearing.

You can also do this whilst connecting a multi-meter to the potentiometer pins, and you will see the resistance change as the motor moves. If there are any dead spots or dropouts, then this could cause the ECU to throw a fault.

Cheers,
Marty

 

[pdg]

Hi
Thanks for the reply
How do I run VE explorer in win xp compatibility mode?
Thanks