Hey guys, 1st time poster, long time lurker.

I have a 99 RX300 with 293k miles. My drivers side heat does not blow hot, the passenger side works perfect. Any ideas?

Thanks
Kenny

 

Also, fwiw I removed the glove box to take a look at the servos. The blend door seems to be fine. Sometimes the car does make clicking noises from down there even when the key is off. I purchased this car extremely inexpensive, almost as an impulse buy. I only have a few more links to work out.


Kenny

 

Sorry it seems no one is responding and what you state is an odd problem.

First Gen Rx does not have individual settings for driver and passenger. So no heat on one side, does not add up.

If you get heat on one side then your blend is working.

What about cold air from AC, do you get that on both sides?

If not then you need to open up the garnish around the shifter to see if the ducting looks ok. Fix may require removing the dash.

If you get Cold on both sides and only heat on one ... then it is a mystery and worth taking to a mechanic.

Salim

 

Thanks for the reply Salim,

The AC doesn't work at all in this car. I figured it was kind of weird to not have heat on drivers side since it is not a dual zone system. I think there may be a crack in one of the hvac tubes... i will investigate.
Kenny

 

I'm in a similar situation. I have hot from the passenger and center vents, warm air from the one next to the steering wheel and nothing from the window one. Will probably have to pull the cluster and lower panel stuff out. Hopefully I find something and diagnose the problem.

 

Did you ever figure your problem out? Im still struggling.

 

Just in case someone comes looking for an answer about this problem. I can only think of one possible rational. I think the system was in defrost mode AND there is low Freon. In defrost the AC is on. There is likely a temp setting near the ambient temp such that hot water flow through the heater core was low flow.

The RX300 does not control the air flow separately twixt Driver/Pass sides. It is simply that the left side of the evap feeds the left (driver's side) and right feeds the passenger.
Top off the Freon using the site glass if it has been a few years. I had this problem a few years back and like others I thought there was a control problem. I spent a lot of time inspecting with temp sensor and usb cameras only to have a duh slap the forehead moment.
EXPLANATION: The evaporator feed (in and out) is on the top left corner as the driver sits. When Freon is low only the top left gets cold.
I topped mine off a couple more times returning the system to excellent cooling but eventually I had to replace the leaking evaporator. See my post on replacing the evap without tearing the dash apart. BTW my AC is still working fine. Have not had to look at it since the evap replacement.
Good luck. BTW I was ticked at myself that I had not checked the Freon first. My sight glass was foam prior to top off.

 

There is only cold air coming from the drivers side while hot coming from passenger side when both turned to max hot. Radiator levels are ok. Any ideas?

 

I had same problem. I found cabin air filter missing, replaced now is much better but still feel variation from drivers to passenger side