93 Climate Control Heat Problems

speedracer · 10-28-06, 12:51 AM

I have been searching but no real solutions come up.

I just bought a 94 TLC and the climate control for heat does not activate all the time (heat sometimes and no heat at other times). What I have found is if I slowly move the control from cold to heat I will get heat.

The rear Heater works fine

I have read about the auto mode HVAC but I do not have this "auto" button. In place where it would be is a plug. SO I will assume there is no auto climate control?

Could the Unit be failing or is a servo failing?

speedracer · 10-28-06, 07:06 PM

oops. It's a 94 TLC

(not 93 as stated before)

archie · 10-28-06, 07:15 PM

I don't have climate control that regulates my temp at certain temprature on my 94 so I can't help you much .Have you checked your coolant levels in the radiator and the resevoir?

cruiserman · 10-28-06, 08:21 PM

Maybe your heater valve is malfunctioning. Your vehicle doesn't have auto climate control. It's manual, which is infinitely better if my experience with our Odyssey is applicable.

speedracer · 11-02-06, 01:31 PM

Thanks for the replies. It's been cold so simple diagnostics take a bit longer.
Coolant Flushed, Thermostate Replaced.
This did help but when I move the controls for heat I will get some heat. I do hear a soleniod noise but if I move too fast it will default back to cold air.

Rear Heater fan is fine.

There is no AUTO feature which is cool. Any other suggestions?
The parts guy mentioned that there was a heater valve in the dash :( But he didn't sound like he was sure - Would any one know?

Is the heater valve a single unit (meaing soleniod as well to operate it)? I've never owned a electronic HVAC so bear wit the question.

Is there any test? The Haynes and the book by Max Ellery has very little info.

speedracer · 11-02-06, 01:44 PM

Heater blows cold.......Need Help!
Found this and will try and see as I do recall seeing it move.

speedracer · 11-07-06, 10:40 AM

Reading this I have a simulair probelm:
Heater valve issues

I ordered a new heater valve.
But I have doubts that that is the solution. Is there not a motor/solenoid that pulls the wire?

IdahoDoug · 11-07-06, 11:04 AM

There is a motor that moves the cable. You can see it at the firewall's center. Have someone move the dash temp lever back and forth and establish that the cable faithfully mimics the lever's movement. If you see something wierd like the lever is moved at normal speed to full hot and the cable moves one way and then goes to cold, you've got a good idea something's wrong.

If the cable faithfully works with the temp lever, then you may have a physical blockage in the valve the cable operates. Pulling the hoses off the valve to see with a flashlight might be worth it.

My money's going to be on this. Your cable has a black housing that clips onto the valve with a spring steel clip. If this clip is loose or incorrectly installed, the cable housing (looks like a bicycle cable housing) can slip and move around which would lead the valve to operate erratically as a result. Take a close look at that before buying an entire new heater valve.

DougM

speedracer · 11-12-06, 11:59 PM

Thanks, I finally was able to take everything apart and also have someone watch for me what happens to the cable when I move it. WhenI move it it moves the correct direction so it's been a mystery as to what was going on.

The cable is attached withthe clip secured onto from the bracket.

Heater Valve removed and cleaned - it was pretty clean, Some brown material on the lever. No blockage. Cleaned and I added a small amt of lithium grease on the back of the arm lever,

Having a friend move the HVAC and it moves back and forth. BUT when he moves it back a bit or forward a bit it will move and then for some reason push forward (cooler).

So my guess is the solenoid behind the firewall BUT after re reading on the clip again I will re check and make sure the clip is secure and not able to move.

speedracer · 12-05-08, 04:01 PM

Took me 2 years to narrow the problem down.

Been way too busy and with racing in the way I never really looked further than the above. Before winter I would make sure it was set so that I could get heat and then after that taped the dial so no one got the urge to move it - lol

Ok - Soleniods are OK. I took the entire dash apart and they work just fine when I supply current to the solenoids. I tested the wires - they all seem ok.

When I check to see if power comes from the Unit - sporadic to no power :(

So - I think the heater control unit is damaged - The big question is where can I find one to replace? I'm up in Canada and TLC used parts just don't exist :( :(

jasonmt · 12-05-08, 08:12 PM

I bought a heater control out of the mud classifieds for $10 so that is where I would start looking.

94SRUNNER · 12-05-08, 09:54 PM

I am not sure how shipping is from the US to Canada, but I would suggest either CDan at American Toyota or CruiserParts.net. CDan is great source for new parts and CruiserParts.net is a good source for used parts.

However I beleive there are a few Canadian LC outfits that advertise on MUD, I would check the adverisers section and you also may want to check the MUD classifieds. You could post a want ad or check the for sale section.

Just a few thoughts, good luck to you.