a/c problems, of the electrical kind - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

stephen p · 06-13-2012, 06:40 PM

hey guys, i hope it's not a problem that my first post is a tech post.. but anyhow, i have a 1993 s13 coupe, bone stock.. and i'm having issues with my ac..

when i first bought the car, it had been sitting for a while, and the p/o had a toggle switch running directly to the trigger wire on the a/c comp. i noticed that none of the lights were on the vent selector buttons, and the gates under the dash did not work.. so a 15 amp fuse later, it's solved, i reconnected the trigger wire on the compressor as it was stock, every thing worked great for a week or so..

started noticing that if i came out during the middle of the day at it's hottest, the compressor would not come on, until i got going down the road for a few minutes, and then it would work fine.. and at night when the temp was lower, it came on immediately.. and it got progressively worse, to where it flat would not come on.. i assumed it was over charged.. so i took the pigtail from the pressure switch on the dryer, put a paper clip in it.. came on as it should have, and it worked for a full day, with me cycling the compressor manually (dumb i know, but i was not near my tools, and i can't deal with the MS heat) so that stopped working.

finally two days ago, i put a set of gauges on it.. sure enough it was overcharged. i let freon out, until the high side was around 230, and low side was 45ish.. (hot wired compressor, ambient temp ~85-90 deg.)

and here's where it's interesting. i pulled the cap of the relay, and manually closed it, to make the compressor come on.. and when i hold it for about 25 seconds, the condenser fan comes on, i can let go of the relay, andevery thing functions as it's supposed to.. and as long as i don't let the car sit more than an hour or so, i won't have to touch the relay again.. i've switched out the relay with others..

anyhow, i realize this is kinda vague, i have a limited knowledge of a/c systems, and i've searched and searched on google.. can't find much. any help would be great..

i don't think there's a blockage or anything.. it blows very cold. also, i've tried hosing the condenser down with water.. it makes no difference with it not coming on.

ka4life87 · 06-16-2012, 11:20 AM

Have you tried replacing the pressure switch on the receiver/dryer?

stephen p · 06-21-2012, 10:46 AM

yeah, switched it out of a parts car, problem seems to be fixed. thanks!

06-13-2012, 06:40 PM	#1
stephen p Join Date: Jun 2012 Location: jackson, ms Age: 34 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	a/c problems, of the electrical kind hey guys, i hope it's not a problem that my first post is a tech post.. but anyhow, i have a 1993 s13 coupe, bone stock.. and i'm having issues with my ac.. when i first bought the car, it had been sitting for a while, and the p/o had a toggle switch running directly to the trigger wire on the a/c comp. i noticed that none of the lights were on the vent selector buttons, and the gates under the dash did not work.. so a 15 amp fuse later, it's solved, i reconnected the trigger wire on the compressor as it was stock, every thing worked great for a week or so.. started noticing that if i came out during the middle of the day at it's hottest, the compressor would not come on, until i got going down the road for a few minutes, and then it would work fine.. and at night when the temp was lower, it came on immediately.. and it got progressively worse, to where it flat would not come on.. i assumed it was over charged.. so i took the pigtail from the pressure switch on the dryer, put a paper clip in it.. came on as it should have, and it worked for a full day, with me cycling the compressor manually (dumb i know, but i was not near my tools, and i can't deal with the MS heat) so that stopped working. finally two days ago, i put a set of gauges on it.. sure enough it was overcharged. i let freon out, until the high side was around 230, and low side was 45ish.. (hot wired compressor, ambient temp ~85-90 deg.) and here's where it's interesting. i pulled the cap of the relay, and manually closed it, to make the compressor come on.. and when i hold it for about 25 seconds, the condenser fan comes on, i can let go of the relay, andevery thing functions as it's supposed to.. and as long as i don't let the car sit more than an hour or so, i won't have to touch the relay again.. i've switched out the relay with others.. anyhow, i realize this is kinda vague, i have a limited knowledge of a/c systems, and i've searched and searched on google.. can't find much. any help would be great.. i don't think there's a blockage or anything.. it blows very cold. also, i've tried hosing the condenser down with water.. it makes no difference with it not coming on.

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06-16-2012, 11:20 AM	#2
ka4life87 Leaky Injector Join Date: Jun 2012 Location: casa grande Posts: 104 Trader Rating: (0) Feedback Score: 0 reviews	Have you tried replacing the pressure switch on the receiver/dryer?

06-21-2012, 10:46 AM	#3
stephen p Join Date: Jun 2012 Location: jackson, ms Age: 34 Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	yeah, switched it out of a parts car, problem seems to be fixed. thanks!