TerrellD

Hello guys! Well I have a 98 civic that the ac doesnt work. I tried the normal things and recharged it.
-the compressor kicks on when I cut the a/c on
-the fan kicks on when I cut the a/c on
-when I switch the controls i can feel when it's cool and when it's on heat so it's trying but I'm not getting anything cool
cool

So ... I'm narrowing it down to either a pressure switch or maybe theres a fuse I dont know about? Oh! I swapped relays in the under dash fuse box and they all checked out good. Any help would be appreciated!!

mk378

If the compressor and the fan both run but it doesn't get cold, it's not an electrical problem.

Check if the low side line is getting cold. If that gets cold but not the air inside you need to check the water valve and air door mechanism as there is stray heat from the heater fighting the A/C.

If the line doesn't get cold either you need diagnose the refrigeration system by measuring system pressures on both sides, and also usually empty the system completely (down to vacuum) and recharge by weight to know the charge is correct. This requires proper equipment. You have ruled out all the easy to DIY stuff it would now make sense to go to a shop.

TerrellD

Alright more information. So I unhooked the high side pressure switch near the driver tire and used a wire to connect them: compressor kicks on. If i unhook the connector to the switch: compressor doesnt turn. When I plug the sensor back in:compressor kicks on. I touched the low side a/c line and it felt luke warm no where near cold

TerrellD

How do I check the air door??? I know it's under the center dash area. The motor that switches from front to feet to defrost works I can see that motor turning how it needs to be

mk378

Read what I wrote again.

DaX

iTrader: (1)

How did you recharge it? Overfilling the system with refrigerant will cause it to not cool properly, just like underfilling it.

tony_2018

@Freedo_Civegra AC guy, get in here.

tamboo

here's a great thread that got mine back on it's feet:

https://honda-tech.com/forums/honda-...-home-1665946/

Freedo_Civegra

Tony, I’m just seeing this.

OP, did you ever get this solved?

muellersfan

As mk suggested, measure pressures on the high and low sides using a manifold gauge with the engine rpm held at 1500.

The pressure readings will guide a diagnosis (e.g., refrigerant leak, compressor, condenser, expansion valve).

sumdewd

If you replace the hot water valve, I recommend going with OEM. I just replaced and adjusted one in our 96 Civic with an Autozone one and it still wasn't cooling properly until I clamped the heater hose.. Go figure.

TerrellD

The culprit as of so far....

Hello guys sorry for the delay so the update. When ac is turned to full on: compressor is on, Id get 30-40psi on low side, clutch relay and condenser relays worked fine as I would switch them and both fans would work. Heating and cooling dash controls worked. When I jumped the high side switch the compressor kicked on as it should. So I tried to recharge the system and I thought I did a pretty good job at it well no cool air. Ok friend suggested replace expansion valve. Cool ripped dash out and replaced it. (Man that was a pain) Put it all back in... same... I gave up last resort. Let me see if a shop can recharge my system since I may have done it wrong. Well took it to the shop and they hooked it up and what did we find? Equalized pressure all around = compressor wasn't putting out what it should so it was fooling me when it kicked on. I'd rather the thing locked up than to give me a false reading. I couldn't test the high side in the beginning since I didnt have a guage for that but you live and you learn so going to get another compressor and slap it in soon.

muellersfan

You would have known the compressor was kaput had you also measured the high side pressure. That would have saved you a lot of time and money given you pulled the dash and replaced expansion valve

Because the compressor failed, you now must do a complete A/C system overhaul if you want the system to work reliably.

Freedo_Civegra

I made a comment on this site awhile back about having never really needed to hook up to the high side in my (now) 17 years of experience working on cars, and it hasn’t failed me yet.

If you had the proper charge in your system and had the compressor coming on, you should have been able to have felt of the low side (the larger one) line at the compressor to see if it was cold.

I’m not putting down anything you did, but this is just a tip for you to use in the future.

Now, when you replace your ac compressor, I recommend changing the accumulator and condenser, flushing the lines and evaporator core with AC flush followed by compressed air, and replacing your high side and low side valves.

You already changed your expansion valve, but I you will need to remove it to flush you evaporator core. I know it’s aggravating, but do it!

muellersfan

Is a manifold gauge set too expensive for a professional mechanic? Why ignore valuable diagnostic information that could help your customers save money and time?

This^ still does not pinpoint the underlying problem, whereas the high side pressure in conjunction with the low side pressure would.

Freedo_Civegra

We have 2 sets of gauges. Almost every time I’ve hooked up to both sides, I’ve already got the diagnosis.


QUOTE=muellersfan;51938948]This^ still does not pinpoint the underlying problem, whereas the high side pressure in conjunction with the low side pressure would.[/QUOTE]

It can. Pressure up, temperature up. Pressure down, temperature down. Is the low side cold and the high side hot? I check that first and, often needlessly, hook up gauges for confirmation. Rarely has it yielded different results than my initial findings.

bloomin

Thanks for taking the time to follow up!!!

Lots of people on here will post with a problem and never follow up with the resolution or solution to the problem!!!!!

Really appreciate it and your follow up will help many others too.

TerrellD

If you had the proper charge in your system and had the compressor coming on, you should have been able to have felt of the low side (the larger one) line at the compressor to see if it was cold.

Funny thing is! At times it would get cool to cold!!! That's what got me thinking the compressor was semi working and I did a faulty recharge

Freedo_Civegra

Glad you got it resolved.

muellersfan

So lazy.

Freedo_Civegra

If you say so...

On my Civic, I only have a low side port. There is no high side. I stand by my method.

muellersfan

Broken high side port?

Freedo_Civegra

V6, custom lines. Didn’t add a high side port.