lostinthew

So after reading all the posts on heat and cooling and the four servos, I had my drivers temperature servo replaced. The entire drivers side blew cold air only no matter the temperature or mode.

After changing the servo and testing both before replacing the old one, the mechanic got readings of 135 degrees on the passenger vent and 108 degrees from the drivers vent (inside the shop) - a major improvement although not what he or I expected. So I drove home.

On the way home I played with the settings and now I still get cold air from the drivers vent and floor. Outside temp 37 degrees.

Pulled into my garage and turned the climate control off. You can still cycle through the modes even with the system off (engine still running). I hear the gate changing behind the vents - should I hear two?

So if it's not the temp servo, what would prevent heat from reaching the drivers side? Why did the mechanic get 108 degrees inside the shop? Is this just my imagination???

Thanks for all your help!

ivnnln

iTrader: (1)

I got the same as your only getting cold air both the pass and driver sides, and once in a while I would get hot air coming out both vents. I asked the dealer and they said it was the air mixture servo one. I replaced mine with both servos since my mode servo was on it way out. If you don't get hot air while dial up the temp to 85 degree, then it's most likely is your air/mixture servo went bad. Easy to replace on mine gs400. Are you thinking of DIY, if so I can help you out?

Good luck.

lostinthew

How tough to DIY?

Thanks

lostinthew

Well, I now have heat on the driver's side!

Here's what happened:

I had heat on the passenger but not the drivers side.

Replaced the diver's side servo motor with a part from Sewell ($140)

Paid my guy at Pep Boys (he used to own and work on Lexus) to replace servo ($130)

Did not fix problem. My buddy recommended that I visit his friends at a specific Lexus dealer for a diagnosis since Pep Boys does not have the equipment to diagnose.

Paid Lexus dealer to diagnose and give an estimate to repair ($139/hour). No electrical problems, so they recommended a power flush as next step. They gave me a sample of my coolant - it was green/brown. It was only 1 1/2 years old! Tech said maybe last guy put in wrong coolant. It should be Toyota pink/red.

Pep Boys does power flush, but my guy said that they run all mfrs coolant through system while Lexus uses only Toyota, a big concern. Did power flush at Lexus ($120) and - voila! heat to both sides!!

My Pep Boys guy said that using wrong or mixing coolant with Toyota coolant can cause gelling and clog heater core.

Total cost - $529.

If I could do it again, with heat on one side and not the other, I would do the power flush first, then diagnose the servo motor functions and replace as necessary. You car geeks might do it differently. I didn't know I had the wrong coolant - I don't do any servicing myself cuz I'm old now. I have to rely upon others.

Hope this helps somebody and saves you some $$!