So my A/c has stopped blowing cold, 95 sc400. I notice it doesnt appear the compressor is turning on, normally turning the a/c on makes the rpm rise a bit in park, and the car will creep forward at low speeds, both have stopped occuring. Do I need to have ac recharged or compressor replaced? Or check fuses? Thanks

 

Typically the compressor won't turn off if it knows the system is low on refrigerant. I'd check that first, try a re-charge, and go from there! Doesn't ever hurt to check fuses as well just in case. As the compressors age they tend to pull a higher amp load.

 

thanks for the reply, just to make sure I understand, the car knows when refrigerant is too low and as such will not allow the compressor to work as a failsafe so it doesnt damage itself internally due to fluid starvation?

 

That is correct, yes sir! Most modern cars have a "pressure switch" that tells the compressor if it's safe to turn on. As far as I know the SC's are no different (someone please correct me if I'm wrong).

 

Interesting info, any thoughts on best replacement solution in this day and age, if thats needed?

 

Would go back with Denso on whatever you need for your A/C. It will cost more but you do not have to worry about one of those Chinese parts going bad. That was one of the reasons I bought my SC for $250. I had to replace everything and it is still going strong after soon be four years. It did cost me more but I do not have any regrets. Denso is what the factory used on our cars.

 

Will do thanks for the tip

 

check the a/c relay, alot of times the relay goes bad and that can happen. usually the compressor will kick on for a second before the high/low pressure sensor trips.
At first it is usually intermittent, you can try giving the relay a slight tap with a screwdriver and see if it frees up or wiggle it around.
Have had this happen on every 4runner and GX I have owned at some point, my old SC didn't do it but those relays are pretty old by now.

 

Thanks Ali, luckily I think I have a spare relay i got all the fuses and relays from a 94 part out a while back, any idea if their the same for all years or different?

 

check the part numbers on them, I think they would be the same as I don't think any of that stuff changed much over the years but I don't know for sure.
If it is the same shape and size prong wise then I would give it a quick try at the least. sometimes its just corrosion build up over the years and the prongs just need a good cleaning and put back in.
sometimes the a/c light will blink if the relay is bad, so that might be another sign, have also seen it blink due to low/high freon too though.
https://www.clublexus.com/forums/per...-engaging.html