Lexus Troubleshooting Questions? Ask a Lexus Expert
My fans and compressor are not working. I have already
My fans and compressor are not working. I have already replaced the compressor AND the ECU, which did NOT fix my issue. I have done some troubleshooting and here is more info: MG CLT Relay has power on both sides of the relay. I should have ground on one side. Does the ECU ground the MGCLT Relay? Since I've already replaced the ECU, what could be causing this? I can jumper the relay and the compressor kicks on. I can also jumper the fans and the fans kick on.
I am sorry that you have not been helped yet. I just came online and saw your question
Yes, the ecu grounds that relay, but I need to get the 17 digit vin number as well as whether yours automatic or manual climate controls to pull the correct schematics for troubleshooting this
Ok, the first step is to test the ac pressure switch. If faulty it will prevent operation of both compressor and fans
I have attached the testing procedure
Ok, that was not mentioned. Please keep in mind that I am not there to see what you have or have not tested and/or replaced. When you fail to provide all pertinent information, I end up wasting your time and mine posting testing procedures and/or repairs for things you have already did.
So, besides the compressor, ecu, and pressure switch, what else have you replaced or tested in trying to resolve this. Please list EVERYTHING
At the body ecu check pin C11 - white with red striped wire for power with ac on and then check same wire at ecu on pin D18
If no power at the body ecu, then check power on pin D20 - black with orange striped wire - at the body ecu
let me know results
You are checking wiring at both the ecm and bcm. the body ecu is behind the driver side of dash - see attached
Ok, sounds good
Ok, at the climate control panel, check the black with orange striped wire at pin 13 with ac on. If power is present, repair wire between control panel and body ecu. If not, replace the control panel
The black with orange striped wire at the Control Panel (Heater/AC Control Unit), has the same voltage as the bcm and ecm. a moving .5-1.5.
One correction...when I unplug the bcm, that voltage goes away.
With the AC turned on via the control panel, the voltage does not increase or change on the black with orange wire.
Are you telling me that the control panel is bad? How much voltage should I have at the wire when at the control panel when the AC is on?
Also, does the moving .5-1.5 voltage on the bcm/pcm wires mean anything?
The control panel is faulty. This wire feeds the bcm, which then feeds the ecm for sending signal to the compressor clutch relay.