A little help: I have no heat.

Yesterday, I had heat. Today, nothing. It's the original coolant with 92k km's on it. Do I need a flush, or is there a fuse or something that could have blown, a relay I need to check? Little help here, please.

 

More info man, like the fan stopped blowing, or the fan only blows cold air, or none of my heater controls are working.

 

Fan works at all speeds, but blows cold air only. Turning the knob to heat does nothing, it's like it's set to blow cold air all the time. A/C works and re-circ works, but there's no heat from the vents.

 

I dont know for sure cause I haven't had to get into mine but it is probably a blend system. Meaning the coolant is always in the heater core and your controls open and close a door in the heater box to allow the air to be heated. I would check the control head.

 

HVAC isn't my forte'. Where's the control head?

 

Check the fuses. I know some of the controls are controlled small electric motors. Just a thought.

 

Could be:

Blend door control
Blend door fuse
Blend door motor
Clogged heater core

 

Does your temp gauge show your truck is warming up to temp? If not it's probably the thermostat. If your truck is getting up to operating temp, then it's probably something electrical, either the heater controls, or whatever Toyota uses to open the hot water to allow it into the heater, a solenoid of some kind. Possibly a fuse for heater control.

 

Yeah, the temp goes up to operating temp. quickly, and stays steady at 87*C. So, maybe a solenoid in the under hood fuse box. Any way to check those out before I drop cash on new ones?

 

Im guessing it may be a thermostat. Mine went out in my old ranger and the heat went away. It usually a cheap part. I might check that. but as said above, normally when the thermostat goes the heat guage stays low. Its actually better for the engine some say, because its cooler? I dunno.

 

I would assume that you may have a clogged heater core. From what I recall, they are placed way up under the center of the dashboard. To get to it, you will most likely have to take it ALL apart to get to the plastic housing. The coolant lines from the engine bay punch through the firewall and head right into the heater core housing.

 

Try fuses first, they are inexpensive and easy to tell if they are bad with visual check. Sorry I can't point you to exactly what fuse to look for, I've never even worked on my Tacoma, it's never needed anything (yet). But I have worked on tons of other vehicles and I'd start at the fuses, then check the things paleus listed "Could be:

Blend door control
Blend door fuse
Blend door motor
Clogged heater core"

Good luck, I'm sure it's something minor. I don't think its a clogged heater core, because I would think that would be something that would go out slowly, not one day work perfect, next day nothing.

 

I agree with the fuses. I wasn't thinking about that cause it all used to be vac when I worked on cars.

 

I've narrowed it down to the blend door. When you switch it from hot to cold on the controls, the door makes a couple funny noises. I actually got heat now, but I'm afraid to switch it to cool now, because it may not come back. How hard are blend doors to work on? Can I do it easily, or is it something that should be sent to a mechanic to do? I have a little mechanical knowledge, but don't know vehicles inside out.

 

It can be a pain in the ass

 

OP, I've got my money on the heater blend door inside the HVAC unit. You may want to read this. http://www.toyotanation.com/forum/6...880-08-c-air-door-actuator-servo-problem.html

That link highlights the recirculation servo but will give you a general idea of what goes wrong. The link addresses one of the more popular servos that go bad.

There are three servos that control 5 or 6 blend doors. The heater blend door part of one of my servos broke and I had to dig it out of the dash.

Most of the servos and blend door attachments can be accessed without tearing into the dash -- that is except the temperature control door. It has a POS little plastic pin that shears off and the only fix is to remove the entire HVAC unit from the dash and replace the entire door. Ask me how I know.

One other thing. The blend doors have foam glued to them and some trucks up to the '09s used a crummy glue that would come unglued from the foam of the blend doors, especially the heater door, and jam open the door, and defrost duct. There are TSBs on both.

Good luck.

 

Thank you. Yeah, it sounds like my problem. Mine is just beginning, but I better get on it. I'll look into getting the heater blend door part from Rockauto. Initially, I thought it was the relay that had gone bad, and the part from Toyota was 160 bucks. And there's two relays! That's 320 for relays that wouldn't have fixed my problem. I'll have to look into the servo motor, it does make strange noises sometimes while switching from hot to cold now, so I'll check it out and see which one it is. Thanks for pointing me in that direction, I can save myself some coin this way.

 

The heater blend door servo is the lowest of the three servos. It is right next to your left foot when sitting in the passenger's seat. You can wiggle the heater nozzle off and out of the way to get more space. I believe there are three screws that hold the servo motor and underneath the servo there is the cam that rotates to position the heater door arm.

The cam operates a lever (the heater door arm) with a tiny, crummy plastic pin I mentioned above. If the pin is broken off you are screwed. If not, open and shut the door by hand to see that it has free travel. The pin is usually broken off when you put it to the max, cold position as the servo really strains to close the door against the foam and seal it.

Standard Motor Products or Dorman produces the servos for these. There are enough numbers on the servo's label to decode it, IMHO, and chase the Standard Motors or Dorman version. When I bought mine the thieves at the stealership wanted $175 for that horrible crappy little servo.