New AC Compressor Not Engaging - 2003 Tacoma 3.4L V6

Hoping someone can help me out here.

My A/C system went out recently on my 1st gen Taco (2003), turns out it was a seized up compressor. I had the system professionally flushed and evacuated, then I replaced the compressor, receiver dryer, and expansion valve myself. Got the truck back running perfectly so there are no mistakes with the part swaps as far as I'm concerned.

BUT, when I went to charge up the system with new Freon, I noticed that the compressor would not kick on. the low side pressure kept climbing to about 70psi and stood still while the compressor never kicked on.

I'm not quite sure what the problem is now. My thought is that is has to be some sort of electrical problem since the fresh freon in the system isn't doing the job to start the compressor.

I've already been through the AC relays in the relay box and everything checks out well, no blown relays or fuses. I've tested all of them.

Thinking it has to be that the electrical signal is just not reaching the compressor itself? Perhaps the wire is dead or not passing current? I can't find any schematics or documents that would help diagnose this problem.

Any help would be much much appreciated! It is too damn hot in this Florida summer to still not have AC despite all the work I've put in already at this point with all the parts swaps.

 

take a test light or multi meter and probe the power wire at the compressor. with the A/C switch on, you should have 12v there.

 

the only wire leading to the compressor is a single wire into the adapter. I can't figure out where to test positive/negative terminals in the adapter. Any help?

 

You'd hook the - lead of the meter/test light to the frame, positive to the contact in the middle of that connector.

 

Corroded connector?? the plug has lots of dirt on the inside Meter probe shows voltage plug it in does not work.

The AC clutch grounds through the compressor to the bracket to the engine.

Is this your old clutch or a new one ?? Easy to check if it works .


You don`t mention your high side pressure ?? Which should equal at this point.

High/Low pressure switch open ??

When you pulled the vacuum you had no problems

 

got it. Turns out the coil is reading .1 V across the connector, so looks like no power was being supplied to the compressor clutch coil. I'm trying to find a wiring diagram to see where the cable harness connects from the compressor to the relay box but it is all threaded through the engine bay and I don't want to go following that wire for hours around all the harnesses.

Does anyone know where I can find some DIY info for removing the compressor coil harness and replacing it?

 

High side pressure did not equalize when I initially began adding new refrigerant to the system, which was indicating to me that the clutch was not kicking on. It is a brand new compressor and brand new clutch. I don't know where the high-low pressure switch would be located. But since it's a new compressor and the power cable isn't supplying any voltage when the car is on and the AC is running, that is telling me that it is an electrical issue with the wire not signaling the compressor to kick on.

 

The high low switch is on the evaporator meaning a pain to get to .

The wire from the AC clutch runs direct to your AC amplifier through two harness connectors according to my 2000 EWD

You should try and get a copy of the EWD for your year truck so frustrating trying to trouble shoot blind at least for me.

 

Did you vacuume the system before charging it? Sometime what it boils down to is that there is not enough Freon in the system to trigger the pressure switch. What you and do is jump the pressure connector with a wire and see if the compressor clutch engages. If it does then add some Freon with it engaged then plug back in the pressure switch and finish charging. Also be careful don’t rush when adding Freon sometimes adding too fast will cause the expansion valve to freeze and it won’t take any Freon

 

from the factory wiring manual

 

You did pull a vacuum after the new parts were installed?/

Maybe you just forgot to mention .

You start charging with the system under vacuum.

Sure sounds like you have a pressure problem

This is why most shops change all the hardware after a compressor failure dirt in any of the coils blockage your done