Hi guys, I have a 1994 4Runner, 3.0 v6. Ac when I turn on it blows normal, but room temp. When I turn it on and look under the hood, it’s not engaging, the clutch.

I wanted to start off by checking fuse and clutch relay , but I’m having trouble locating it. I’ve look in the side panel inside on the driver side and in the engine compartment. But when I look through it, and use the diagram as reference nothing mentions the AC fuse 10A and clutch relay. Where else could this be and any thoughts on my issue with the ac?

 

The compressor clutch will not engage if the refrigerant low pressure switch does not permit it.
Have you connected a set of service gauges to the system and determined if any refrigerant charge remains???

 

The AC fuse is in Relay Block 3. https://web.archive.org/web/20120417.../2powersou.pdf

Does the light on the AC switch illuminate? Then it's not the fuse.

As Millball points our, you are most likely out of refrigerant. You would need gauges to tell. https://www.harborfreight.com/r134a-...set-58776.html

 

so my idea was to check electronically first. I will try buying a refrigerant that has UV dye to see if any leaks are present as well. What do u think?

 

hi, I’m in the 4Runner now, engine warm….im pressing the ac button and it’s not turning on. So I’m assuming AC fuse. Any other possibilities? And should I still test refrigerant?

 

I don’t know if your truck is new to you or not but just in case, did previous owners ever say they serviced it? Replacing the seals is key on an older system like these. They won’t even hold any new charge you try to add if it doesn’t have new seals everywhere.

You can try the uc dye but for the most part people find that these systems are dead on arrival. It’s best practice to replace condenser and dryer with more efficient/effective ones as well as all seals; then recharge.

 

I’m open to that but I need AC for now. She’s my fault and she is new to me. She only has 120k miles. The UC dye I was gonna use to see if there was any leaks, any leaks maybe at the compressor which would be bad, I’m just trying to mark off any potential possibilities

 

If your system is low enough on charge or empty, the clutch will not engage even if your fuse is good. Good luck with your truck. Please follow up with whatever you find.

 

Jfaya,

As mentioned, there are 2 main possibilities:
- Bad fuse
- Low system coolant pressure

This could also be complicated by a bad light bulb in the AC switch.

You didn't mention if/when it last worked. If it has not worked for a while there are many other possible issues. My recommendation, unless you are familiar with AC systems, is to take it to a recommended shop and have them do a quick test of system pressure. If that shows empty, then a vacuum test to check for leaks. Depending on what that shows you can decide how much you want to spend. There is also the R12 or R134A question. Do you know what it was previously filled with because they are not compatible.

I have attached the schematics for the system if that helps troubleshooting.

Good luck!

Jim

 

It turns on and it blows when I turn the AC on. It just blows room temp. Not cold. I am in texas and it gets got here. Under my hood there's a sticker that says R134A is the refridgerant.

 

Update I tested AC fuse and relay, both showed correct measurements. Going to get a gauge to measure refrigeration levels and use dye to see if there is any leaks. Ac dash light works now , cleaned up the ac fuse a little, debris. Ac blows but like i said cool/room temp, not cold cold.