my readings are 110 on low and 150 on high. When I jump the compressor I get thing about correct with 35-45 on low and 250 on high pressure side. I was told I had a bad relay and purchased a relay and this did not work. air get a little cold is all.

Why won't the compressor kick in?

I think there is some blockage because the only way to get compressor to work is to jump it.

Any one know what I should do?

 

Try jumping a shorting wire across the connections on the hi/lo pressure cut-out switch. It's near the receiver/drier near/underneath the battery. If this enables the compressor to run, the pressure switch is faulty and should be replaced.

I think you'll have to discharge system to replace pressure switch.

good luck

 

I did the jumper on switch that plugs into I ac line under battery as recommended & compressor did not kick on. with the switch jumped again I jumped relay and it kicked on. so hi /low switch is good. this one has red white & blue yellow I checked ground with directions below and ground is good.

Should i check the a/c button on dash? this button lights up when i hit it.
Found this:

All a/c systems have a pressure switch. Its actually on top of the reciever/dryer on that car. Thats the cylindrical aluminum thing just under the battery tray.

The ground comes through the a/c switch on the dash. than goes through the thermostat in the evaporator housing and through the pressure switch. If either of these 3 things are bad they wont tell the PCM to turn the a/c on and the PCM wont turn the clutch or fans on.

The first thing i would do is unplug the pressure switch. It has 2 wires a blue/red and a blue/yellow. Turn the car on. turn the a/c on and check for ground at the blue/yellow.

 

You said you jumped the relay, did you test the inputs to it? Are both fans coming on when you do this.

 

Suggest jumping ground directly to the red/blu wire to the compressor clutch relay. This should cause the relay to engage and compressor to run and would confirm that reason for no AC compressor clutch engagement is the ECM thinks the pressure switch is open and is denying ground.

Possibilities are open red/wht wire from pressure switch to B5 pin on ECM or faulty ECM.

I assume when you jumpered the relay you jumpered Wht to Red (power side of relay).

good luck

 

Ok we tested the ac system and ran the compressor by jumping at the relay. System pressure is now good and we added some 134A.

1. Still have problem with Compressor kicking in.

2. Fans do not come on when we have ac turned on.

Presure switch has no good ground when i do the jump nothing happens.
I checked the blue / Yellow has no ground.

I also grounded each one at a time and both fans came on when I ground the red /yel. I was told the switch inside car works with both fans & compressor.

I jumped the thermostats plugs the one up front did nothing the one back by firewall I jumped and both fans came on.

I wanted to post this and will now study they last reply and the ECM & #6

How do I check the switch? can I by pass it ?

If it is bad ground where do i look next?

with the switched jumped i checked for ground at relay red/blue & power at other 3 and bad news.

 

You said you jumped the relay, did you test the inputs to it? Are both fans coming on when you do this.

answer I have been jumping on Red / compressor wire & Black yellow & compressor goes on but no fans

TX Honda asked me to ground direct to red/blue & I did and it ran compressor but no fan.

so am I to look into ECM ?

 

Check Fuse No 4 (7.5A) and No. 8 (7.5A) in the under dash fuse box. If these are open, the fans would be disabled and AC thermostat would not close.

Suggest checking the AC diode first. If it were open the cooling fans would not engage and no signal to the ECM. AC diode is on the left side under dash above the kick panel. It should show high resistance in one direction and closed circuit in other when checking resistance of component. Separate from circuit to test.

Another possibility is faulty AC thermostat (open). It's basically a relay and a temp sensor.

Your test proves the relay is fine. Just no ground signal from ECM. It's either not getting signal from open diode or AC thermostat.

good luck

 

If you have a volt meter, unplug the electrical connector for the a/c pressure switch. Check that the red/wht wire has 12V to body ground when the key is in the II position.

Also, the blu/yel wire should be grounded (zero resistance to ground, or closed circuit to ground).

I would use the valve cover bolt as ground or the negative battery post as my ground.

Let us know what you find.

 

Looks like we are getting down to the last components thanks.

I would of never know how to locate the Diode. Then I found this

A/C Fan Issues with 94 RS: Diode location? - Honda-Tech

I have checked the fuses more then once; but will again.

So the front a/c Thermostat connector that I tested unpluged with a paperclip is also failing because of a bad ground?

The rear a/c thermo test ran both fans.

I will post results!