2nd Gen Non-Engine/Transmission No Heat

[hilda]

Have no cab heat, so far replaced thermostat, removed glove box, both sides of heater core are hot. I believe I have located electric motor for the blend box. I have no voltage there while trying heater in various positions. Am I in the ballpark maybe dash switch is bad? How do I get the back screw on the trans hump off to remove the motor to manually open the door?



Thanks in advance



Hilda

 

[georgej]

I don't think the blend doors are activated electrically. Check your vacuum lines from the pump to the firewall. Sometimes there is a problem right over the exhaust manifold with a melted fitting that will prevent vent changes inside the cab. Good luck!

 

[Thomas]

The dark blue wire (terminal 1) in the harness that is connected to the blend door actuator should have 12 v. present when the key is in the run position. It is fed via fuse #2 (10 amp) in the junction block—that door at the left end of the dash.

Does the fan run?

 

[hilda]

Thanks Thomas that is the info I needed. Took dash apart today, have voltage going into the switch but noting out on any of the three connectors that lead to the blend door motor. I'll double check the blue wire tomorrow. Yes, the fan works.

Is the #2 fuse for the fan and the blend motor?

 

[hilda]

I don't think the blend doors are activated electrically. Check your vacuum lines from the pump to the firewall. Sometimes there is a problem right over the exhaust manifold with a melted fitting that will prevent vent changes inside the cab. Good luck!

Your right George, the AC Blend door along with the vent doors work on vacuum ,but the heater blend door is electric. I'll be an expert when this is all over. :-laf

 

[georgej]

Learned something new on the TDR today. Whatta website! Thanks

 

[hilda]

Drove to work this AM and had heat for the
first time. The blem door motor is bad. I removed it
and opened the door manually and have lots of heat.

I did have 12V on the blue wire of the plug, so I
figured the dash heat switch is ok.

Does anyone happen to have a blend door motor?

Hilda

 

[Thomas]

. . . I did have 12V on the blue wire of the plug, so I
figured the dash heat switch is ok. . .

As my initial post in this thread states, the dark blue wire should have 12 v. present when the key is in the run position. Looking at my wiring diagram it sure looks as though the A/C—Heater Switch has nothing to do with the 12 v. (or lack of 12 v. ) being present on the dark blue wire—you would still find the 12 v. with a bad actuator and/or a bad switch.

 

[hilda]

Took the blend motor apart, what a piece of C**p. There is a small servo motor inside, it's bad and the connectors to it wow, lets just say it's made in china. I did measure the voltage at the servo motor connectors and as I turned the heat dial from cold to hot I was getting 12v + one way and 12V- the other way. I would think (I could be wrong) that this would be the correct voltage for this motor.

 

[hilda]

Thanks Thomas

It was the blend motor!!!! Found a wrecking yard that knew what I was talking about and purchased the motor for $35. 00 including shipping, this beat the dealer price of $155. 00. Installed it over the weekend, and had a nice warm heater on the way to work.

Now on to the other issues with the new truck