Thank you so much for the offer. Based on Richard's test, looks like my ECM pinout to the fan relay is working, but maybe the ATC is not sending a signal to the ECM when the AC is on.

Sounds like a plan, but first let me get the tools to remove the radio, as you get to the ATC thru the radio hole, right?

And what are the head gasket codes? I've had a MAF sensor code for a while (3-4 months), and now I've had the ODBII reader on the truck continuously for the past week, I have seven (7) more relating to O2 sensors and air-fuel mixture (I think). Hoping they are just related to the MAF.

It did overheat (red warning light came on) while idling for 15-30 min in 95-100F heat -- that's how I discovered the condenser fan mud wasp issue. Not sure how hot it got as I didn't have my ODBII reader with me when it happened. It's not consuming coolant that I can tell, there is no white smoke and no milky oil on the dipstick.

Good news is it can't slip a sleeve as it already has top hats in it. That's how we got it: a prof at UT overheated it, slipped sleeve 7, got a quote of $8,000 (more) from LR dealer in Austin to fix it, so just gave it to my son if he would move it out of his driveway. $2,500 rebuild and 6 years and 60,000 miles later and it is still going (mostly) strong.

 

I find it easier to do by removing the cluster of switches on the left and the clock to the right of the ATC itself. You slide an old credit card or similar above and below the clock to release the tabs and then yank it out. The switch cluster thing on the driver's side is a little easier, but both take some finagling. Once those are out you will see the silver tabs on the sides of the ATC which get pressed in and allow the ATC to slide out.

Headgasket codes was a joke. Perhaps a bad one, or at best dry, but I was kidding.

Sounds like you got a great truck. No rust down that way either.

 

Alright, been out of town for a while, just got back to the D2 today.

An update.

It looks like my ATC ECU might have been bad.

I picked one up used (from the junkyard, didn't want to bug you Ahab for the loaner you offered), installed it, and now the condenser fan runs whenever the AC is engaged -- and not just when the engine exceeds some temp (somewhere between 95 and 100C).

BTW, your suggestion about releasing the ATC thru the sides (by popping out the clock on one side and the switch cluster on the other) rather than from the top thru the radio hole was great advice: those spring clips are pretty strong and much easier to release when pushing on them from the sides instead of from above like the RAV suggests.

So after replacing a burned out condenser fan (lesson: if your car sits for a while, check to make sure mud daubers haven't built a nest in the electric fan housing), the engine fuse box (probably not needed, so now I have a spare) and the ATC ECU, it looks like the electric section of my engine cooling system is fully functional again.

Thanks all for the help everyone.

Now I can turn to upgrading the thermostat.