Changed AC components, light still blinks

2006 V6 Tacoma 6spMT
My AC stopped working and the AC light blinked. Can't find the culprit. Here's my order of troubleshooting.

- Checked the pressure and it was super low. Charged it with R134a with leak seal, still didn't work. Held pressure after that, though.
- Swapped the relay with one of the surrounding relays, didn't work. Also ran power to the relay and it clicked, so assume it's working.
- Bypassed the pressure sensor switch with a paperclip.
- Changed the Compressor Pickup Sensor on the compressor. Light still blinks, compressor doesn't turn on.
- Bypassed the relay and the compressor kicked on but after a while of driving, the compressor made a whirring sound.
- Replaced the compressor, condenser, and expansion valve. Recharged the whole system with proper amount of PAG 46 oil and R134a and some dye.

Light still blinks and the compressor won't come on unless I bypass the relay. I'm going to just order a damn relay, but man, I'm getting frustrated here. I have a 1600 mile road trip into the desert coming up in about 3 weeks.

Anybody got any ideas???

 

Just swap the relay with an identical one under the hood.

How are you charging the system?

Whenever I'm helping with 2nd gen tacoma a/c I always have a motto "It's the damn compressor" It's rarely the high/low switch, relay or controller. 99% of the time its the compressor. Just because its new doesn't mean its good.

 

What year and engine is your truck?
Your gona have to check your wiring from the clutch relay and compressor to the A/C Amplifier, I can post the wiring diagram if I know your year and engine.

 

Unless he has changed trucks. It’s an 05’ w/ 4.0
https://www.tacomaworld.com/threads/wtb-05-6-speed-shifter.158465/

 

Yup, 2005 4.0 6spMT.

 

Swapped the relay this morning. Didn't work. There are only 2 more culprits that I can think of: The pressure sensor and the sensor at the evaporator. After that, I'm out of ideas.

This is insanely frustrating. I'm thinking of taking it to a shop or dealer, but I don't really know if they'll be able to help, and I don't want to pay for nothing.

 

Just tried bypassing the pressure switch with a paperclip. Still nothing, so the switch is probably fine.

So now I'm down the the sensor that's on the evaporator coil. Gonna have to figure out how to test that. I found this thread on how to change that without removing the entire inside of the truck, but I don't want to just keep changing parts:
https://www.tacomaworld.com/threads/a-c-performance-during-highway-cruise.446835/page-3

Can anyone think of what else it can be so I can add it to the list of things to test?

 

What kind of compressor did you replace with? Either Denso or factory?

This issue is either at your climate control unit or it's the AC itself. As stupid as the AC setups are on these trucks I'll say it's the compressor first, even though you replaced it already.

 

The flashing A/C light is when the A/C amplifier does not detect a speed signal from the compressor lock sensor after commanding the MG CLT relay on.
Possible causes are:
Open or shorted wire(s) in the lock sensor circuit
Bad lock sensor
Internal problem in the compressor
Open or shorted wire(s) to the MG CLT relay
Failed A/C amplifier

You will need to check your wiring
The MG CLT relay should have power on pins 2 and 5 when the blower switch is on, the A/C amplifier grounds pin 1 to turn it on.
Also check the wiring between the lock sensor and A/C amplifier.

 

I'm adding the AC amplifier to the list of things to check.

It's a UAC brand. I got it from RockAuto and it's a popular brand for this truck.

 

By lock sensor, I'm assuming you mean the compressor pickup sensor. That's been replaced. Compressor is new. I'll check the AC Amplifier and and then check wire continuity. Thanks, man.

 

Yes the wiring diagram calls it the lock sensor but service info calls it a pickup sesnor, it's the same thing.

 

The A/C amplifier is behind the glove box on top of the HVAC housing.

 

Ok, found it. Ordered a used one for $75.
Oddly, the bracket part of the amp's housing is cracked and it was just hanging there. Not sure what would have caused that.

I'm also having issues with the blower fan speed, in particular speeds 1-3, but not max. I'm already familiar with this problem. The connector that controls the fan speed has a burned connection at one wire. I'm going to clean that up and hope removing the residue on that connection fixes that problem. I think it's just affecting the connection, not necessarily a broken part.

I'm starting to consider taking apart entire sections of the truck and refurbishing the wiring and several parts. It'll be cheaper than buying a new one, plus I've had this one since I bought it used in 08 and have done quite a lot in this truck.

 

You might as well replace the resistor too. That’s the most common cause of what you are experiencing. Settings 1-3 do not work but High is fine. It’s because the resistor is bypassed on High.

If the connection at the blower is burned. It wouldn’t hurt to check both the fan and resistor connections. I’d probably check the connector for the switch as well. It’s not hard to get to.

 

well, I'll be damned. Only $23 for the resistor and connector. I think I'll do that.

$19 Dorman 973-582 HVAC Blower Motor Resistor Kit Compatible with Select Toyota Models

https://www.amazon.com/Dorman-973-5...t=&hvlocphy=9051904&hvtargid=pla-493007214156

 

Don't expect the Dorman to last too long but it will work for awhile.

 

@Jimmyh knows the updated part numbers I think.

 

Thanks Jimmy.