The search feature on this forum always returns no results.

I recently got a 96 Accord that was wrecked and repaired in the left front section of the car. The A/C does not work.

Here is what I know:

--The wire bundle under the ABS pump shorted out, (they pinched the wires during the replacement fender install so it wore them through, I repaired all the burned out sections. (so I think)
--The A/C clutch relay was bad (I assume burned out when the wire bundle fried) so I replaced it
--All fuses are good.
--The common ground point inside the left fender behind the blinker light is connected and is a good ground.
--I am getting 14v to the clutch. I put a load meter in the sequence and found that the 14v wire goes to ground when connected to the A/C compressor, actually it is showing a -.0 on the display. Is this what should happen?

During troubleshooting I ran a wire directly from the battery to the compressor, it will engage the clutch, the low pressure lines get cold, stuff seems to work.

Using the repair manual I checked the wires, from the relays and they are fine.

When I get to checking the voltages at the ECU, it mentions checking the B5 line. The diagram I have of B5 is a yellow color. The manual says if there is no voltage to repair the open wire (red/white) between the A/C diode and the ECU.

Here is the problem: The wire at B5 is not red/white, its yellow. AND I cannot for the life of me find the A/C diode that is supposed to be right behind the left kick panel.

Can anyone give me assistance finding the diode, and maybe a better ECU pinout diagram so I can properly identify the B5 connector. I do not have access to the test set the manual suggests I use.

What else do I need to check? Could there be an internal fault in the A/C compressor? Why is the 14v lead supplied to the clutch not working? It seems like there is not enough amps?

 

Do the fans come on when you turn the a/c on? 4cyl or 6?

are you sure your looking at the right connector? should be the 31pin I think it's blue.

edit... I would ck for ground at pin 4 at the relay. the ecm provides ground to the relay. it does not give it power.


Modified by vapor40 at 6:55 PM 7/11/2008


Modified by vapor40 at 7:01 PM 7/11/2008

 

Its the 4 cyl with VTEC. Yes, both fans come on.

edit: The blue connector is the "C" connector in the picture I am using.
edit: I checked the blue connector Pin 5 and it is red/white! Either way, YES there is 12v from the ECU at Pin 5. The next setp in the manual said to check with a good ECU and see if symptoms are gone. I got another ECU, and the problem STILL exists.

edit: I checked the ground to the relay from the ECU and yes it IS providing a ground to pin 4.



Modified by siafu at 11:28 AM 7/13/2008

 

Thanks for the help. I edited my post above with the answers to the questions.

edit: where is the diode really? I cant for the life of me find it behind the left kick panel.

 

Still no luck. I even checked the thermostat now and it is fine, along with the pressure switch. This sucks!

 

I re-read your first post. You have battery voltage at the clutch already?

 

To answer your above question, no. I must have mis-typed the OP.

I have narrowed it down to the ECM ground problem. As soon as I manually ground the red/blue wire I get my +12V to the clutch and everything works.

I was reading this post:

https://honda-tech.com/zerothread?id=2329420
I checked my thermostat in the evaporator, it functions just like it is supposed to as far as on/off is concerned.

I checked the signal from the thermostat to the ECU, and it is good.

I am now back to the ECU. I already replaced the ECU once witha used one, so I find it hard to believe it is an ECU problem.

When using the manual for troubleshooting it says to measure the VOLTAGE from the ECU and body ground. I am getting +12V from the red/blue from the ECU. I thought this was supposed to be a ground signal??????

I am completely confused!!!


Modified by siafu at 12:02 PM 7/14/2008

 

send me you email address, I will send you a pdf from the honda service manual. It is a step by step diag.

 

Thanks!


Modified by siafu at 3:28 PM 7/18/2008

 

Hi Siafu,

I'm having a similar problem with my 95 Accord. See my post:

https://honda-tech.com/zerothread?id=2347044

I've narrowed mine down to either an ECM or ECM ground issue (though I remain skeptical about that) or a problem with the evap sensor. Other than that, I've run out of ideas.

On the ECM angle, does anyone know which wire supplies the ground to the A/C clutch relay from the ECM? On the wire harness that plugs into the A/C relay, there's a black w/yellow stripe, red (to compressor), white, and a second red w/blue stripe.

Thanks!

 

Hello tdenneson! After everything I went through, we got it narrowed down to the A/C thermostat. I thought I checked it fine, but apparently it is not. We hotwired the wires from the thermostat and the A/C blows nice and cold. I am going to replace it and hope it fixes the problem.

As for the question you ask about the wires, Ground travels through the fan speed switch to the A/C button. From there it travels to the thermostat inside the evaporator housing. Then it goes through the pressure switch.

If you unplug the pressure switch and apply ground to the Red/White wire does the a/c come on?

 

Hi Siafu!

Thanks for the response. When I would jump the pressure switch, only the condensor fan came on. Now that I've added refrigerant to get it up to "normal" range pressure (which I was able to do while jumping the black/yellow to red to get the clutch engaged), the fan comes on without having to jump the pressure switch, which makes me think the switch is working as it should. However, the clutch still does not engage. The red/blue wire with the dim signal I described is coming directly from the ECU, according to the wiring diagram I have.

If your fans were runnning but your clutch was not, I better take a second look at my thermostat. I ignored it because I assumed that the fan would cut out too if it was getting cut off at the thermostat. Do you mean the thermostat behind the glove box? Do I have to remove the evaporator to get to that?

 

I would definitely look at that thermostat behind the glovebox. Here are the instructions I used to get to it without draining the system:

https://honda-tech.com/zerothread/1652895

They are about 2/3 of the way down the post.

Good luck. It's actually quite easy.

 

Thanks Siafu! I'm going to take a closer look at the thermostat. It's good to know that it's possible to replace it without removing the evaporator!

Let me know if this fixes the problem for you as well.

 

I discovered that the white wire running to the A/C relay was not providing juice, even though it should be hot at all times. I fixed that by splicing it into the white wire going to the condensor fan relay (they split from the same junction having a common origin anyway). However, that did not fix the problem. Apparently I have multiple issues going on.

I'm trying to test the evaporator thermostat. You said you "hot wired" it to get the compressor to run. Which wires did you connect? There's a Blue/Yellow, Blue/Red and Black/Yellow in the plug going into the sensor/thermostat. Thanks!