OK I went threw all the test in the manual http://media.honda.co.uk/car/o...0.pdf
Theres no leak in the system , all new lines ,good compressor, good pressure switch, good relays. I pulled vacum for 2 hours at 29 lbs then let it sit for another 2 to see if it leaked out and its good. If I hit the compressor with direct power it turns on and I traced it down to maybe the ecu. I hit B3 (a/c clutch relay) at the ecu to ground and the a/c clutch engages so according to the manual I need a new ecu. My ecu works fine its just that one thing. SO is it bad if I were to just hook up B3 straight to ground cause wouldnt the pressure switch be the one controling the clutch ???? http://media.honda.co.uk/car/o...8.pdf

 

anyone ?

 

intresting I am having the same problem but I thinks its because I dont have enough freon in I only have 15 psi while comprssor is cycling

 

low on the cfc and the ac compressor will not cycle.

 

thats whats driving me crazy We tested everything like 4 times for 3 days everything is good except that wire coming from b3. do you think if I ground it will the pressure switch still make it come on and off ? What does the ecu actually do for the a/c ???

 

bump

 

ttt

 

so if your system is not leaking and you have the correct amount of r12 and your wiring is good, might be the clutch took a ****. It should cycle on and off. If it doesn't cycle it must be that the compressor is bad or not correct amount of r12.

 

checked the amount of r12 every day to see if it leaked & it hasnt so thats out
If I ground B3 the compressor comes on so I think its the ecu I dont really have extra $$ to buy a new ecu cause this car isnt registered yet & the G is my daily can any one tell where I can find out what b3 does ??? is it a constant ground ? does it ground it self when the a/c switch is on ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by BoostedEF &raquo;</TD></TR><TR><TD CLASS="quote">What does the ecu actually do for the a/c ???</TD></TR></TABLE>

The ECU grounds the compressor clutch internally....Trust me it's a pain in the but to trace and diagnose, but try and run a known good ECU for a few days and I'll bet your A/C will operate flawlessly.

 

FWIW, try this also...
I am still hunting for the right page with the ecu pin-outs...

 

Huge I.M. sent...lol...

 

I guess Im going to try my ls ecu

 

ok I checked the grounds and there good I changed ecus and still nothing!!! Every test checks out ok but for some damn reason the compressor isnt kicking on. Fans turn on and everything should I just ground the b3 yellow wire (a/c clutch) ?? Im going to hook up some guages and ground it out and see if something cycles it off or if pressure starts to build up anyone have any ideas ?

 

TTT, this man needs his A/C fellas...

 

How do you know the compressor clutch is good? I have bought compressors in the past that were said to be "in good working condition" but never were. Something was always wrong with the clutch. Try buying a brand new compressor and see if that fixes the problem.

 

its a brand new compressor and I was thinking that too but why would it work if I hit the compressor with power straight to the red wire & hit the yellow b3 with ground at the ecu ??? some thing dont add up

 

Im having the same issue someones please ehlp

 

**** it I hooked up the yellow to ground & its working till when ??? dont know its also not getting that cold & its R12 I thought my sack would have been frozen lol everything still reads good and tests are good

 

Have you bypassed the pressure switch? Blu/red to Blu/red. Its an input thats not allowing the ECU to ground internally. It looks like the fans will still run despite the compressor not being on due to the use of a diode. Grounding B3 will bypass the ecu and pressure switch. An overcharge or undercharge will affect the system. Try that and let me know.

 

Im going to try and cut b8 and see if that gets b3 to work

B8 Blue/Red a/c pressure switch also goes to one side of the coolant temp switch on the block but turns into yel/green wire which turns into ground when the switch reaches a certain temp right and activates the fan relay to turn the cooling fan on
its seperated from the bule red wire by diodes
im going to look for the diodes and see if i can test them

 

Cutting B8 is the same as a bad pressure switch. You are eliminating the input signal. Id still try and jump the pressure switch
&lt;p&gt;

 

ok your getting that diagram for someother kinda car but anyway
so according to that and other diagrams when you hit the a/c switch it sends out a ground to the thermostat that reads it and passes it to the pressure switch that reads it and sends it to the ecu and threw the diodes & to the condensor fan relay fans are turning on when the switch is on so its going threw the diodes so its probably not getting to the ecu to send the signal that the a/c should be on holy crap I think I just figuered it out when I get home Im going to try all that crap I just said The manual never told you to test for ground at the ecu

 

Actually thats for a 91 Crx directly from the ISIS Honda site. The Ecu gets inputs from the pressure switch and coolant temperature sensor. When turned on,this tells the ECU to ground out and send ground to fans and compressor. The ECU is the ground. The diode is one way so the fans will still run even if the compressor is not on. I still think your fault is in the pressure switch. By grounding the compressor clutch relay,you are bypassing the pressure switch and ECU.

 

Ok but doesnt the presure switch get ground from the switch side and when it sees pressure it opens and grounds out the ecu side ??? Im thinking theres a break in the wire where it goes to the ecu