Heater quit... sort of

[Helmutt]

Would you please post the before and after photos of the heater control circuit board. I seem to have the same problem. Thanks

Originally Posted by dfluitt

Hi Wizzer. The Toyota dealership here in Santa Rosa California charged me $55.00 to diagnose my Highlander's heater problem. They said they would have to order the part and I could bring the car back next week to get it fixed. I asked him how much it would cost and he said that he was embarassed to tell me that the heater control unit was going to cost $681.00 dollars to replace. After I picked myself up off the floor I asked him if that included labor. He said the labor would be another 165.00. The total to fix the car? 55 + 681 + 165 = $901.00!!!! And this doesn't include tax...
I did some research last night and came across this site and your post. It took me all of one hour this morning to pull the control unit out of the dash, open it up, solder in three new wires, and put it all back together. It works Great!!
I took my wife out to the movies tonight to celebrate the money we saved. I think the most satisfying part will be tomorrow when I call the dealership to cancel the appointment to have the car worked on.
Thanks again for your taking the time to post your Highlander experience here.
I took several pictures of the insides of the heater unit showing the before and after of the broken wires and the fix. I can post them here if anyone wants to see what the circuit boards look like and where the wire needs to be soldered.
Thanks again.
Don

[Fixit]

Thanks for this solution and the images as well. I'm seeing in a lot of posts about this problem and it appears that a great deal of these vehicles are driven by women as is the case with mine. What are the two most important things women want in a car? 1) Reliability (The reason we bought a Toyota!) and 2) HEAT!! (The one thing never dies in any car!) So why is such a fundamental function going south in the supposedly reliable Toyota? I asked the parts people and dealership managers and no one knows. They just play dumb and shrug their shoulders, as usual. Unfortunately this won't be recalled because it isn't a safety issue so they suggest calling the Toyota customer service group which I will do and I encourage everyone else with this ridiculous problem to do the same. Apparently they made good on a problem with the run flat tires on the Sienna vans that caused them to get like 10 mpg. It's great that everyone is getting together to help each other on this but at $1000.00 to fix a defective factory part Toyota needs to address this. I’ve owned a dozen Toyotas in the last 25 years and never had such a stupid problem with one! Maybe they should go back to cables and vacuum lines!!!

Originally Posted by dfluitt

Here are the photos documenting the heater control fix. The first shot is of the panel with the knobs removed. The nut that comes loose is under the knob and holds the shaft steady. The loose nut allows the small circuit board behind it to rock back and forth when the knob is turned causing the wires to break.
The second shot shows the back of the heater control unit with the cover removed showing the main circuit board and the small circuit board (circled) on the back of the control knob.
The third shot shows the ribbon cable where it breaks off at the solder joint on the small circuit board.
The fourth shot shows the three wires I soldered in place of the ribbon cable.

[LifeTech]

I can see that Toyota subcontracted out this HVAC conrol to "Sumitomo Electric". They produced a sub par in quality item.

Although a bad design, It is a money maker for Toyota.

It's quite amazing that this item fails consistently after warranty is up!!!!

Question: If this control is responsible for the defroster settings, would that be considered a SAFETY Issue?

If yu can't see out of your windshield due interior fogging and/or exterior winshield frosting, I would see that as a SAFETY ISSUE!
A vehicle defroster which is part of the HVAC system IS required equipment for ANY vehicle.
Temp adjustment needed for any defrosting system!!!!!


My spin...

LT

[browntermite]

I own a 2003 Highlander. Same problem as the other posts. No heat except when in a certain position ( not even then at times ). The nut behind the dial was very loose. After reading all the posts concerning the fix, I took it to a mechanic friend. We tore into it, resoldered the connections, and it works perfectly now. Thanks so much for all your helpful posts and allowing me to save a bunch of money.

[charly105]

Hi I have a 2002 Highlander which has 48,000 km on it and the heater is also doing what you have all discussed. I talked to our local dealer and again they said about $1000.00 for the heater control unit. I basically said I would rather go without heat than pay this. Why did I spend $43,000 off the lot to have a vehicle which is such a poor design. I will take the unit out and try to fix it myself. This is the first time I have had any issues with this suv, but I certainly am thinking about ever buying another Toyota.. too bad I thought they gave good service that was fair,, but I am certainly wrong. I even gave the technician the fix that you have here, and they still said no I needed to replace the unit, and I am sure they never even looked at the back of the unit. I have also contacted Toyota Customer Service and am taking this to their review board, and I agree that this should be a recall because I live in Northwestern Ontario and if you have been up here when it is 30 below you will freeze, and certainly the windows will not defrost, so this is an issue of safety..
I will let you all know how I make out with this problem. Contact the customer service department and complain... maybe we can get a recall if they get tired of us...

[fsammartino]

I also want to add my thanks for the $900 this thread saved me!
I'm a bit of a novice, and was unsure about some things even after thoroughly reading the posts, so here is a little summary of the steps for other non-mechanical types like me. This is the situation for a 2003 Highlander:
1) the "bezel" - refers to the large plastic piece that goes around the heater controls and radio, and includes the 2 vents (grills and all!) on either side of the heater controls. I started from the bottom where the bezel is narrowest and easiest to grab, and slowly pryed and gently pulled it out. I used a couple of those cheap disposible plastic putty knives for the hardest part around the vents on top, until it had come out enough to grab with my fingers and evenly pull out the rest of the way.
2) remove 6 bolts, and 2 screws from the aluminum brackets on the sides (also pull apart the aluminum brackets enough to get past a couple of positioning posts), and the whole heater/radio unit pulls forward enough to easily remove the 3 connectors plugged into the back. The heater unit then comes out complete with a plastic bezel piece that goes around the radio
3) 8 screws and the back cover comes off the heater control unit.
4) I pulled off the knobs only after I had the whole heater unit out. My heater control was so loose that I was afraid I'd break it when I had to force the knobs off. But the knobs do pull straight off - I used a couple of small screwdrivers on either side for leverage to gently and evenly pull off my loose knob
5) the soldering was a little tricky, because the wires are small and close together. Use 24 or 26 guage stranded insulated wires for the patch job, along with a sharp-tipped soldering iron. I used a wet spong to clean the hot iron tip each time. Also it helps to first melt a drop of solder into the bare wires at the end of your new jumper wires. That makes it solder easier and quicker to the circuit board, so you minimize the amount of heating you do to the circuit board.
6) the whole operation took me 2 hours, but I could probably do it again in 1/2 hour now that I know what I'm doing.

Good luck and thanks for the tips everyone!

[eng_dude758]

Another satisfied reader! I'm so glad I came across this site cause I just spent $8.65 for a soldering iron instead of $865 for a new environmental control assembly for my 2001 2WD Highlander! Thanks to the user who posted the pictures!

[koschik]

Originally Posted by wizzer

My 2001 Highlander heat just became quite intermittent. I have the manual temperature control version with the 3 knobs, not the automatic climate control. There is just one little place on the dial where the heat comes on full blast. It seems to move around and the heat will work for a while then stop. Then I adjust the knob around and find the hot spot and the heat works fine for a while. Except that it is full on. The fan works fine and the control for where the heat is directed also seems fine.

Anyone with experience with this? Is there a part I can replace? Does the dash panel around the heater radio, etc remove easily? And if so how? Anyone know of a reasonably priced source for any parts that I might need?

Thanks

I don't have a solution for you but have exactly the same problem on a 2002 Highlander and the dealer recommended a very expensive solution of replacing the entire heating control unit.

Did you ever get yours rectified economically?

[HILDR56]

Thanks to Wizzer & Dfluitt for their posts!

My '04 Highlander had the same symptoms (and root cause). Following their explanations and pictures, I repaired mine today using only a few screwdrivers, a soldering gun and lots of patience. A zero dollar D-I-Y fix vs an expensive dealer repair.

[hesparza]

I have a 2001 Highlander and my wife has been complaining about the heater not working for a while now but everytime I used it, it worked. I had to turn the nob a few times but I got it to work. Then this morning I decided to drive it to work and sure enough the heater worked off and on. Air changed from hot to cold. After reeding wizzers comments, I remember I took the nob off 1 time and found the nuts were loose. I tightend them but nothing changed. I can't wait to get home and remove the panels to look for the wires. Thanks for the info and I'll post back when I'm done if I had success. Great details and thanks for the images posted Wizzer. It makes it easy to see what I'm going to remove and work on.

[ThePhog]

To echo what many said. This morning on the way to work, my heater started blowing cold air. Not good times, bad times. I made an apt w/ Toyota for tomorrow, then googled something like "Highlander heater blowing cold air" and it directed me to this site. Well, I printed out all 6 pages of this thread (about 70 pages or so) plus the attachments included on page 1. I took all of that to a local auto-shop and asked if they would solder the wires as described. The old guy thought I was crazy, but after 15 minutes, that's the problem, one of the wires was cut.

Thanks for tip, it cost me $60 to have them solder it for me, as I'm negatively useful at that sort of thing.

[LifeTech]

This is a great sticky.

This thread gets the award.

Another happy ending.

LT

[skylars]

Just took apart a heater Control from a 2003 Highlander and found the wires broken from the Temperature Control to the Circuit board broken. Re-soldered the wires and everything is now working great. The control loosens up which causes ribbon cable to break.

[edwardh1]

Do Many 03's or 04's have this problem? did Toyota do a fix on it yet?

[tfreid70]

I had the exact same problem on our 2003 Highlander and took the unit apart and resoldered the wires. Thanks all, especially Wizzer for posting the solution to this one. This saved a ton of money!!!