RichS

I've hunted the forum and the web and am surprised that I can't find anything on replacing the relays on my 2010 RX350. My A/C stopped working yesterday, and I want to get the magnetic clutch relay before bringing it to the dealer for troubleshooting.

I know where the relay is, but pulling the top of the under-hood fuse box off gives access to the fuses but not the relays tucked up underneath it. Is there a way to access them without pulling the brake fluid reservoir?

If I can access them - I'd also like to swap some relays to troubleshoot, before buying a replacement. The guy at the parts counter said the horn, fog lights, and fuel injectors use the same part number. I don't see anything that appears to have one of those labels, but another parts schematic showed 3 relays with the same OEM part. Can anyone identify/confirm these descriptions from the fuse box lid for the relays:

DEICER - ?
IG1 - ignition
MG/CLT - Magnetic Clutch (for A/C - what I'm trying to test)
ST - ?
AIR SUS - Air Suspension? (empty, I assume - I didn't check)
RR DEF - Rear Defroster
C/OPN - ?
IG2 - Ignition
RDI FAN 1 - cooling fan
F/PMP = Fuel Pump

Also - the left 2 rows of fuses (the bigger ones) have red covers over them that seem to be locked in place. I loosened the nut in the lower left of the box, but that didn't free anything up. Hints on accessing these fuses? (One schematic I found includes A/C as affected by at least 5-6 fuses - I want to check them).

Other thoughts on easy A/C troubleshooting.

Clutchless

I doubt anyone here has your answer, but you may learn something at the Toyota Highlander forum as they are mechanical twins and more of those folks are shade tree mechanics that work on their own vehicles:
https://www.toyotanation.com/forum/1...ion-2008-2013/

salimshah

The hardest things to find are the ones that do not exist.

The relay if used as a generic item ,,, then the clutch itself is the relay.


Salim

afpj

Do you have a code reader that can read B series codes like techstream? There's a thread on this forum regarding the sensor in the ac compressor assembly not outputting enough voltage so the controller keeps the clutch from engaging.

Clutchless

This is the thread https://www.clublexus.com/forums/rx-...-solution.html

RichS

Huh? What doesn't exist?

It's part #5 on the 2010 RX350 Switch And Relay schematic
Lexus part number 9098702028

I'm not sure what's unclear about this. I'm asking how to access it.

I'll check the Highlander forum if there are hands-on folks there.

RichS

Yes, I had found that. It deals with a faulty sensor on the compressor itself, which won't engage despite a signal, as the voltage has dropped from the flow sensor. I'm troubleshooting upstream, hoping it's the relay that sends the signal is faulty - much cheaper than replacing a faulty part integral to the compressor. If I can confirm the relay is working, then this is a possible next cause, but I'm hoping it's upstream/cheaper.

RichS

With some help from my daughter, I verified the fog light relay clicks when the fogs are turned on (it's under the dash), as does the rear defroster, in the same cluster as the AC switch, but the AC relay does not, so I'm more hopeful that's the problem

Still open to ideas on accessing the relays.

OBD-2 is based on CAN isn't it? My code reader works fine on my other cars, but not on the Lexus. It's probably 10+ years old - was there an update to the CAN spec in the late 2000's that may render mine useless for newer cars? I guess I can stop by Autozone at some point, though I'm not getting any visual indication of a thrown code.

(For those who are curious - this is what I'm trying to do. The same P/N is widely used in Lexus/Toyota models. Lexus just made it much harder to get to than shown here (start at 1:05).

wechslerl

II have a question for Salimshah
How do you gain access to the relays of the 2016 RX that is under the Brake fluid reservoir, without removing it???

wechslerl

I have a similar question.
Do you need to remove the brake fluid reservoir to access the relay box in 2016 RX 350 !! ??

salimshah

I have 2011 RX 450H. I will check it out, but my answer may not be applicable for 350.

Salim

wechslerl

I believe the two cars are Identical in this issue!

Mesquite77

On my 2008 RX350, I remove the brake fluid reservoir to get at the relays, only 2 or 3 screws hold it on.

wechslerl

Thank You very much Mesquite77