AC Compressor Won't Turn On After Replacement

[scoostraw]

Hi guys.

2008 Toyota Tacoma 2.7l - my AC died the other day with loud SCREEEEEECH! And the AC button started blinking.

I went ahead and replaced the compressor. After drawing a vacuum, I tried to charge the system but the compressor is not being commanded on.

I verified that the pressure switch is closed (zero ohms) and I have about 70 pounds from the R134a on the low side. The AC fuse is not blown. The AC button no longer is flashing g.

If I jumper 12v directly to the compressor it starts and runs fine.

Something is preventing the compressor from being commanded on, but I don’t know what - and I don't have a wiring diagram.

What am I missing here? Any ideas?

[tbirdtbird]

How deep a vacuum?
Was the pump the compressed air powered type or run by an electric motor?
How long did you pull the vacuum?

When a compressor grenades, you also need to replace the condenser (they cannot be flushed) because the debris from the comp will get trapped in the cond (it acts as a type of filter), and possibly even be transferred further to the TXV or OT and clog it

[Cusser]

2008 Toyota Tacoma 2.7l - I went ahead and replaced the compressor. After drawing a vacuum, I tried to charge the system but the compressor is not being commanded on.

I verified that the pressure switch is closed (zero ohms) and I have about 70 pounds from the R134a on the low side. The AC fuse is not blown. The AC button no longer is flashing g.

If I jumper 12v directly to the compressor it starts and runs fine.

Something is preventing the compressor from being commanded on, but I don’t know what - and I don't have a wiring diagram.

What am I missing here? Any ideas?

1. Get a wiring diagram.

2. You said that the pressure switch is closed (continuity) at your 70 psi, good. But are you getting 12 volts positive TO that pressure switch when the engine and AC are switched on?

[DetroitAC]

Check your AC clutch fuse and relay, if your compressor seized, the screech was the clutch slipping, it gets super hot. The coil melts and releases, designed to do this so your accessory belt doesn't break and you can drive on your way with the windows down. When the coil melts it can short out, should blow the fuse, might also take the relay with it,

[Tim]

This gentleman is an ACKits.com customer. He seems to have done the basic steps. I suggested yesterday he purchase a Mitchell single-vehicle subscription for the wiring diagrams. He mentioned he might have a friend that has an R & R machine. Could possibly try and have it charged using the machine if it is a pressure issue causing the switch not to trigger.

COMP SP15 PV7 05-09 TOYOTA TACOMA. I don't think these have debris issues, and the cond/drier are not serviceable. So replacement only if determined it is clogged. I'm still leaning toward a wiring issue.

[JohnHere]

The system could also have generated a trouble code when the compressor seized that might be preventing the the PCM from commanding the compressor "on." Have it checked with a scan tool, and have any codes that might have been recorded cleared.