matt1969

i have a problem with my blend door motor or what ever is causing this.i replaced my evaporator a few months ago and have either full cold or full hot.i took of motor to free up blend door that was a little jammed up.ever since i got every thing back together i have had this problem.just past center its either cold or hot.not a show stopper but id like to be able to adjust it.ive searched the forum but i have not seen this question answered.i have set it in the middle and left battery over night.did not work.thanks for any help.
2001 quad cab 4x4

biododge1

well, i'll try to help. let me get into the book and see if i find something for ya
stay tuned....

matt1969

nobody has solved this problem?

WestTN

It sounds like the position sensor is broken. All or nothing is the usual response when a balanced bridge circuit fails.

Break Away

Take off the motor that moves the blend door and test it with your temp control button.

mcctho21

I did the exact same thing when I replaced my A/C evaporator. I didnt get the rod lined up in the hole that the blend air door rode in and I turned the motor with a half inch wrench. BAD NEWS... I opted to leave the whole dash in there and drill a whole to push the rod back in the hole with a welding rod. Kind of shotty at best, but it worked. Now that got the door back in line, but didnt solve the problem I created with the wrench. When I turned the servo motor with the wrench to set the blended air, I stripped it out. I went to the junk yard and found one. Hard as all get out to put them in or take them out mounted under the dash like that. It seems to work OK, but sometimes when I put all the way to Hot, it wont come back off of it unless I reach down, without crashing, and spin the silver shaft a little on the servo motor. Then it will take over itself. Not sure *** is going on there, but that is that. A small right angle philips, lots of patience, of which I never have any, and 80 bucks for a new one, will get you fixed up I suspect. Unless you never installed it right in the ductwork when you split the ductwork open. If that is the case, then you know the drill. Get yourself a Haynes (not the best) manual and look up the heater core instructions I think. Good luck. PM me when you leave a response, so I get an email to get back to the thread as I dont get on here very often any more.

matt1969

same thing i did .but i cut a small hole i could fit my had in to pop the door in place.i took the motor of so i could move the door with out hurting the motor and now all i have is hot and cold,but it works for me i was just seeing if there was a easy fix.

Tommy93w350

I did the same thing, I kept using a wrench to turn the door and stripped the bottom off the door. It's stuck in the middle hot/cold. I just replumbed the heater hoses to keep the hot out so the a/c would be cold. Now, my a/c is so cold I run it on low and sometimes cut it off for a while to warm up in 93 degree weather. Best mod yet

I have a new blend to install, waiting to the end of summer.

Tazman

Hey guys,

Is the blend door on my "98 a manual operator or servo controlled?

As I turn the temp **** it activates a lever via cable.

Am I looking in the right place for a blend door problem? This sucker will not put out heat in the winter and now the AC is pretty much useless.

Any help appreciated.

Cheers,

Taz

R.T.D.H.S.P.

Yep...It's the control and door out of contiguous alignment.

AggieJustin

So did you just reroute the plumbing that feeds the heater core to bypass it? Or just shut off the supply to the core?

Would there be an issue with just putting a valve in the supply to the core and closing it when you don't need heat? Would this cause a problem since the line from the core back into the system would not have any flow?