85 XR A/C Rehab. (Long) It works! No it doesn't! It is now! Nope, it quit again!

[zxr250cc]

Hi all,

I looked around and found the site for the substitute I mentioned:

https://redtek.com/12a/

Cheers

[justpushplay]

Another update coming, involving leaky Schrader cores, valve core remover/installers, Nylog, and knuckles vs. hot E3 exhaust manifolds! Also, an A/C system that finally kicks ass. Consistently. Now, once the parts arrive, can I keep the freon IN the system?

[justpushplay]

Ta Da! The last update! Wherein the bumbling Merkur owner finally banishes the system of leaky things. Ed wins again with the Nylog recommendation. One of the obvious leaks was in the high/low side Schraeder vales on the compressor itself. I have been using a right angle R-12 Schraeder-to-R-134 adapter on the low side of the compressor, (the new receiver/dryer has an R-134 high side connector integral to the unit) and consequently had two of them come loose and disappear on test drives. Poof. Sytem empties in secondsI had not put in schraeder valves with these adapters, as the adapters I had had no provision to depress the schraeder valve. I quickly realized that I would not be able to leave the adapters in place, they unscrewed themselves every time. I put the original Schrader valves back in, only to have one leak after charging with the adapter and removing it. The little cap would stop the leak. I didn't want to pull down the system AGAIN (I've lost count how many times I've done this) so I bought one of those cool little things that allow you to swap out the valve while remaining charged. Great! Pays for itself in saved freon, right?! I bought new Schrader valves and rehearsed a couple times with another compressor top plate, and it work perfectly. At least until you realize there is NO working room to use the damn thing in the XR engine compartment. (eye roll) At this point, I decided to replace every O-ring in the system with the exception of the condenser/trinary switch connections. I used Nylog on all of the O-rings, and that finally took care of the myriad teeny tiny leaks I had been experiencing. Meanwhile, the de-ice switch replacement switch continues to work perfectly, the temp sensor 'inside' the evaporator's core feeds the right temps to the thermostat, and it all works seamlessly. The vent temps are steady, you are never aware the compressor is cycling at all. Just really cold, consistent temps. I also have a functioning recirc valve now. I just needed to reverse the hoses on the solenoid itself. Another big 'DOH' moment.
Pics and links here:

https://www.ebay.com/itm/391815747024
https://www.ebay.com/itm/235655540295
https://www.ebay.com/itm/165331287833

[Ed Lijewski]

Cool!!

YMMV

[justpushplay]

Yeah! Literally

[petenhxr4ti895spd]

? What about the relay source?

[justpushplay]

Inkbird ITC-1000 12V 10A Temperature Controller


https://www.ebay.com/itm/391815747024

https://www.amazon.com/s?k=Inkbird+ITC- ... nb_sb_noss

Hey Pete! Here ya' go:
This is a nice little unit, and very inexpensive. It works seamlessly in place of the failed Ford device. I mounted it inside the car, inside the dash next to the stereo. Buy two, in case it fails at some point. It appears that it's built quite well, and the internal relay is rated at 10 amps. So this thing is running way understressed. The load on it is just closing the relay I added to the side of it for the A/C system. That in turn, via the trinary switch, energizes the clutch on the compressor.

The relays were these: https://www.amazon.com/dp/B017VDI0GY/re ... UTF8&psc=1
These Bosch style relays are plentiful and cheap. I've used these on my boat for the hydraulic trim pump and the engine cover lift ram, and they have worked perfectly for several years now.

EDIT: There's now a whole 'nother thing going on with this since adding the LA2 ECM. The green WOT relay in position 3 at the power distro/fusebox gets pissed off and just makes grumbly noises when the ignition is switched on. The easy fix is to remove the green WOT relay, and just jumper at the relay socket. Jumper from the center pin to the pin next to that on the driver's side. Bingo, fully functioning A/C again. You DO lose the protection of the WOT function. I'll be gutting a relay, and make the jumper internal to the relay housing. I hate the look of the jumper wire, can't have that bailing wire look on an XR!

[petenhxr4ti895spd]

You showed a 4 or 5 pin cube relay with mount. Where did you purchased that?
Who rebuilt your AC compressor?

[justpushplay]

Here's how I jumper'ed the angry WOT relay socket. I am now no longer protected by the WOT function, but A/C functionality is restored. Just turn off the A/C if you wanna play boy racer and bang shifts at 10k rpm:-)

[petenhxr4ti895spd]

Thank you for the infor.
I removed the WOT function too get my AC functioning again.
I am looking into, why the the ECU is commanding the #3 relay too shut off the ac.
From the information I have it only states, that the maximum TPS position will command the relay #3 too shut off the AC.
? Do you know of any other sensor, that command the relay #3 too shut off the AC.

[Ed Lijewski]

Two:

- a failed de-icing switch;

- a bad trinary switch (connects to the receiver/dryer)

Neither of these is ECU controlled.

YMMV

[justpushplay]

What Ed said. Ed knows things that only a Merkur owner could possibly know:-)

[petenhxr4ti895spd]

The Trinary switch is in working order.
The de-icing switch is in working order.
Its just a relay.
these two devices are in line control circuit devices.

[justpushplay]

? Do you know of any other sensor, that command the relay #3 too shut off the AC.

Pete, are you running the stock computer, or one of the L series? Reading comprehension hasn't been my strong suit this week:-)

[Ed Lijewski]

The Trinary switch is in working order.
The de-icing switch is in working order.
Its just a relay.
these two devices are in line control circuit devices.

Those are not relays.

They are Switches (On/Off).

They are not ECU controlled.

The ECU, if it sees the TPS voltage return is ~4.5v (indicating the throttle is wide open), opens the WOT relay ground cutting off current to the a/c compressor.

If everything cited above is "working" (as you say) but your compressor your doesn't operate, it could be because:

-- there is insufficient refrigerant charge in the system (so as some)

-- the compressor clutch is faulty (test it by connecting 12v from the battery direct to the clutch: if it actuated, it's good; if it doesn't, it's bad.

YMMV