I have done a few R12-R134A swaps. The '90 4runner with '94ish engine needs a/c for the fiance. So I started the adaptation and fill procedure (hose fittings, and bottle with gauge) The gauge went into the red, and the compressor did not kick on. (Sometimes it takes awhile for the pressure switch to kick power to the compressor) The green light is active on the a/c in cab switch. So I hot wired the pressure switch thinking the switch was bad. No go. So I turned truck off and hot wired the compressor, and it clicked. I fired the truck back up and hot wired the compressor, charged the a/c system, and it holds the charge (no leaks!). But it still is not getting the power from the wire it is supposed to in the harness?.... Where is the fuse and "breaker" people speak of??

 

on my 88, theres 2 fuses on the blower or the heater core box itself... its been so long since ive had the dash out i forget which one. but even though mine doesnt have a/c, its got the wiring and the fuse for it. check there.

 

thanks, will do

 

The fuse for the a/c is good, so is the front and rear heater fan relays, and the breaker.... what else could it be?

 

The wiring to the AC compressor??

 

Magnetic Clutch relay... would be the first thing i'd check. Make sure you're getting power into, and out of it.

 

pb4ugotobed, where might that relay be?....

 

I just did a little research, and sorry, there is no relay for the clutch like in all the newer yota's (that have a major issue with those relay's failing). The "relay" is built in to the AC Amplifier in your truck. However, I'm attaching this EWD that may be of some assistance to you.

Edit: It won't let me attach the file because it's 64kb and a maximum allowed is 48kb. But if you PM me with your email address I'll email it to you. It should tell you everything you need to know, and everything you'll need to check to find out exactly where you're losing your signal at.