LJ78 more A/C questions... (1 Viewer)

[Jarrat]

I've read up most of the A/C stuff on here.

Checked the system before adding Red Tek, was at 29 PSI, I then bought the stuff thinking it might activate the pressure switch and then it would work.

So far I've

- Tested the clutch with 12V - OK
- Red Tek added up to 35 PSI with clutch manually enabled. (which wasn't very much)

Still doesn't seem to blow cold.

I guess what I'm asking for is..... does anyone have a wiring diagram?
or the A/C diagram specifically for my 1990 LJ78?


Thanks in advance.

 

[GTSSportCoupe]

Did you follow the Red Tek instructions carefully? I should go check what pressure I put in mine. Also, A/C doesn't blow very cold unless lots of air is flowing across the condensor in the front. Mine works best when highway driving, or idle up at stand still to get the clutch fan pulling some air.

Here are the wiring diagrams that I have:

 

[Jarrat]

I followed the instructions up until I started the truck and tried to fire up the A/C and the clutch still didn't engage, so then I assumed maybe the pressure switch might have pooped the bed, so I manually turned on the clutch and continued to fill the system until it went a tiny bit over 35 psi and let it run for a while, even with the RPMS up at 2000. The condenser seemed to get hot, but inside it didn't blow any noticble cold air.

I can't seem to make out everything on that diagram. Is it from this book?

http://www.ebay.com/itm/Repair-Manu..._DefaultDomain_15&hash=item1e79aa6fe6&vxp=mtr

Thanks for your help so far.

 

[jblueridge]

There is also the thermistor which decides if things are hot enough to warrant activating the compressor.
On my BJ74, this thing is in with the evaporator.

My evaporator had some crud in the fins and needed a good cleaning. I got some foaming cleaner from a HVAC supply store.

I also replaced the expansion valve just to take care of any possible problems.

 

[Rummat81]

On mine, the high pressure switch was toast, had to replace that. i also did a complete rebuild of the compressor due to the O ring leak and front seal leaking badly.
i used acsource.com for rebuild kit and supplies, it was back in 2010. drier was off an older corolla model. if nothting breaks you can do a rebuild with new parts/valve for arounf $250. Assuming your condenser and evap are fine. make sure to remove and flush them thoroughly with spirits.
the compressor model is 10PA15 i think, verify yours first.

 

[Jarrat]

Thanks guys.. I feel really dumb posting this, but I found the problem. Seems the previous owner used the A/C fuse somewhere else as the spot didn't have the 10amp fuse in it. Blows cold now even at idle.

All together I used maybe half a can of Red Tek to bring it from 29 Psi up to 36psi while the pump is running. I'll check it again after driving it for a week in this heat.

Thanks again for all your help, I love this site and the people on it!

 

[GTSSportCoupe]

I can't seem to make out everything on that diagram. Is it from this book?

No, it's from the Toyota manual for our trucks. RM183E I think. Only place on the web I could find it was here: http://www.landcruiserparts.co.uk/t...&category_id=8&option=com_virtuemart&Itemid=7

Definitely buy it. It's worth the $10. Covers everything but the engine.

Also, I found the Toyota manuals for the 1990+ 2L,3L,5L and 2LT. I downloaded them, and now I can't find them online again. I'll have to find somewhere that will host them for me so you guys can use them too. Was great to use while I re-did the head last week. Much better than the 2LT/3L manual that only covers the early rocker cam version of the engine (the easy to find manual).