I am having issues with my fan on my 1998 LS400. Recently it started where the fan is stuck on low, even though I change the climate control fan speed to high. I did a AC system diag code, and it came back fine. I tested the voltage on the controller.

I tested the controller as specified in this document:

http://forum.ih8mud.com/attachment.p...1&d=1226121968



The voltage doesn't change from Pin 2 to ground when I change the blower speed control.
Also from pin 4-5 when the blower speed changes the voltage doesn't change.

Does anyone have any ideas on how I can fix this. Since the voltage never changes when I change fan speeds I think it maybe it is not the controller but something in the climate control.

FYI Pins 1-2 go to the fan, pin 3 is ground, pin 4 changes the fan speed somehow, and pin 5 is the positive power to the fan.

 

I fixed the issue turns out the cell phone hookup in the trunk can actually toggle off the fan speed to low. I unplugged the unit and everything is happy.

 

Did you plug the two large connectors together after you unplugged them from the phone ECU? Not sure if it is necessary for everything to function properly but that is the way they are in cars without phones. If you want to get the phone ECU connectors up and out of the way, they are normally attached to the bottom of the tool box housing -- there may be a plastic bracket on the bottom of the tool box housing unless the phone installer removed it -- see the attached photo.

Funny, I gave the same advice today on another forum to someone with a similar but not identical fan speed problem. Turned out that he didn't have a Lexus phone. Yours is only the third or forth time I remember someone verifying that a defective phone ECU caused his blower fan to stick on low speed.

I've wondered which pin in the phone ECU connectors triggers the blower fan speed to go to low and if the trigger is when that pin is grounded by a call in progress -- like another PIN in the large phone ECU connectors is grounded to automatically mute the audio system during a phone call. I've wondered if I could attach my phone kit's mute wire to lower the blower speed as well as mute the radio. Someday I'll get out the ol' test light and multimeter and find out.

Don't know if it is of interest to you, but the center front pin of the phone connector on the driver side under the armrest is an audio system mute pin that can be used with an aftermarket Bluetooth phone kit.