ok guys did a search didnt find what i was looking for. MY engine came with the ac but the stand alone harness i have does not have provisions for it so do i use the third gen wirng and incorporate it to the 4th gen ac or do i use 4th gen ac wiring? i still have my harness that came with my ls1 thanks!

 

I like using the 4th gen wiring. All you have to do is provid the PCM with the trigger wire from the thirdgen wiring. I believe its a green wire up by the blower motor wiring. Once the PCM gets the signal that you want a/c.....it handles the rest. There is only one pressure switch in the 4th gen a/c system.

However, Im using ALL 4th gen parts. Hoses and everything. But I think if you are using the 4th gen compresson on your thirdgen parts, you just treat it like the thirdgen compressor. I think... There should be some write ups in the swap stickies or around here that say what you have to do there.

I know I read up on it several times before I started messing with mine.

J.

 

THanks for the response your reply makes sense sounds like the better route thanks!!!!

 

if you are running the ls1 a/c pump you just wire it up just like the f-body 4th gen your pcm is for..

you can get the needed three wire psi switch from most of the older r12 FWD gm cars (such as 1990 pontiac grand am vin a or d) this shows the pcm what it needs to see. and this will screw right on to your current thirdgen a/c pipe running just above the k-member. it does not get any better than a switch that fits correctly and uses the same connector as your 4th gen wiring


i do belive if I remember correctly the wire is green for the (on ) signal like stated befor. it's one of the two at the cutoff switch mounted on the dryier if you want to use a meter while selecting a/c

 

thank u thank u thak u