A/C compressor clutch not engaging

[floralvikings]

Hey this is interesting. I went out to get for something in my glove box just now, and noticed two wiring harnesses coming out by my ecu, not plugged into anything whatsoever... I doubt it has anything to do with my a/c but I'm wondering if they should be plugged in somewhere... Running next door to get my camera really quick and I'll post a pic

 

[RonJ]

I have to rant here a little bit. I found a guy who says he has my car, exactly, same year, make, model, trim, transmission, everything, in his lot, with ECU in, and he'll give me the ecu for $45. So I'm freaking stoked, even though it's like 45 minutes away (closer to an hour in traffic) I'm out the door. I get lost looking for the place because it's kinda sandwiched in between two other junkyards, but I eventually get there.

And the freaking car is an automatic. ARGH. And it looks like the cheapest I can get one online is about $70, and there's no guarantee that it'll even work.

[EDIT]

Oh, and mine was wrecked awhile ago, so I was kinda hoping this car would have the parts I need to finally finish it off, but it's freaking missing literally every part i want.

Ask the guy if he would loan you his ECU. Maybe he would agree if you offer him $10 or $15 or a 6 pack of beer. I say this because installing the auto ECU should tell you whether your ECU is the cause of your A/C problem.

 

[floralvikings]

Ask the guy if he would loan you his ECU. Maybe he would agree if you offer him $10 or $15 or a 6 pack of beer. I say this because installing the auto ECU should tell you whether your ECU is the cause of your A/C problem.

Crap, I should've just tried putting it in there shouldn't I? Well, I guess I can head back out there on monday, they close at 4 on Saturdays and there's no way I'd be able to make it.

 

[RonJ]

Crap, I should've just tried putting it in there shouldn't I? Well, I guess I can head back out there on monday, they close at 4 on Saturdays and there's no way I'd be able to make it.

Yes, the engine will run with an auto ECU, allowing you to test whether your ECU is the problem.

 

[RonJ]

Hey this is interesting. I went out to get for something in my glove box just now, and noticed two wiring harnesses coming out by my ecu, not plugged into anything whatsoever... I doubt it has anything to do with my a/c but I'm wondering if they should be plugged in somewhere... Running next door to get my camera really quick and I'll post a pic

The lower picture is of the service connector that you jump to pull CEL codes and adjust the ignition timing. I forget what the other connector is for, though everything is fine the way it is.

 

[floralvikings]

The lower picture is of the service connector that you jump to pull CEL codes and adjust the ignition timing. I forget what the other connector is for, though everything is fine the way it is.

Ok awesome. Just checking

 

[floralvikings]

Whelp, swapped in ECU, still not coming on. What's next? Getting voltage @ both wires still.

 

[RonJ]

I need some clarifications.

The only problem is that nothing comes on.

I thought the condenser fan runs but the compressor clutch does not engage?

I currently have a toggle switch rigged up to directly turn the compressor on

Is the toggle switch still installed? If so, describe how it is installed.

Okay, swapped the relays. In one configuration, the condenser fan is coming on with the a/c switch, so I know it's not the HVAC controls. But, no matter which relay is where, the compressor doesn't come on.

So in the other configuration, even the condenser fan does not run? If so, that's the problem -- bad relay.

I tried jumping the compressor power to the condenser fan, and it engaged no problem, blew cold, everything a-okay.

What did you jump to what in this test?

What's next?

Answers to the questions above will be the guide.

Getting voltage @ both wires still.

What are the voltages?

 

[floralvikings]

I thought the condenser fan runs but the compressor clutch does not engage?

So in the other configuration, even the condenser fan does not run? If so, that's the problem -- bad relay.

This, exactly. With the relays in the original positions, nothing. With the relays swapped, condenser fan and nothing else.

Is the toggle switch still installed? If so, describe how it is installed.

Took it out when I started to tinker with it, didn't want it in the way. Was basically using it to test what was working and what wasn't when I was repairing and replacing parts.

I guess I didn't explain myself well enough about the relays. Know where I can get them reasonably priced? I figure that since one is bad I should replace both of them, right?

On the bright side, the new ECU seems to have seriously helped my running rick problem, I just worked a 6 hour shift with about 200 miles driven and very very little blackness on rear! ^.^

 

[RonJ]

This, exactly. With the relays in the original positions, nothing. With the relays swapped, condenser fan and nothing else.

I guess I didn't explain myself well enough about the relays. Know where I can get them reasonably priced? I figure that since one is bad I should replace both of them, right?

The relay which, when inserted into condenser fan slot, does not allow the fan to run is bad. You can just replace it, but replacing both is probably a good idea. Call different auto parts stores to compare prices.

Replacing the relays should restore A/C if the bad relay is the only problem.

 

[floralvikings]

Will the relays out of a coupe from the same generation work or should I get them from a sedan? The reason I ask is because I have a friend in Oklahoma with a 95 EX coupe; he took the A/C out and still has all the parts, and he might give me the relays if I pay shipping.

[EDIT]
Just found the answer!

[EDIT 2]

Actually, there are a TON of cars that use this relay. Can't believe I didn't look into this before. I should have replaced these months ago >.<

Oh well, live and learn.

 

[RonJ]

Will the relays out of a coupe from the same generation work or should I get them from a sedan? The reason I ask is because I have a friend in Oklahoma with a 95 EX coupe; he took the A/C out and still has all the parts, and he might give me the relays if I pay shipping.

[EDIT]
Just found the answer!

Make sure the cost of shipping is not more than the price of buying new relays.

 

[floralvikings]

Make sure the cost of shipping is not more than the price of buying new relays.

Yeah shipping was about $7 and autozone wanted like $150 for both, o'reilly's wanted $80+ for both, only junkyard that would warranty wanted $80 for both. I think i did pretty good. And there are a couple of pairs on ebay that are less than $50 shipped. So I've got options even if these don't work, but I'm willing to gamble $7 on a chance to save $40+

 

[RonJ]

The equivalent 6th gen relays cost from $5 to $15 each at Majestic Honda. Your 5th gen relays cost about $33 each at Majestic. I don't know why the 5th gen relays are so expensive.

 

[floralvikings]

The equivalent 6th gen relays cost from $5 to $15 each at Majestic Honda. Your 5th relays cost about $33 each at Majestic. I don't know why the 5th gen relays are so expensive.

WOW that's MUCH cheaper that anything I was looking at new. Yeah it seems weird that the 5th gen relays are so much more expensive

 

[RonJ]

WOW that's MUCH cheaper that anything I was looking at new. Yeah it seems weird that the 5th gen relays are so much more expensive

You also need to add shipping and handling (S & H) charges for purchases at Majestic Honda. You save the most money there by making bulk purchases because the S & H charges don't increase much for a large order compared to a small order.

 

[floralvikings]

Put in new relays. Condenser fan coming on, and the engine idles down a couple of hundred rpm when I turn it on, but I can't feel the compressor kicking in and the air didn't seem to be getting cold at all, although I only ran it for a few minutes as I was kind of in a hurry



What else could it be? To recap, this is what I've tested and tried...

1) If I jump power from the interior fan switch to the compressor, the compressor comes on.
2) I've replaced the ECU
3) ECU receiving voltage from the compressor clutch relay
4) Sending voltage to the heater control panel, though I can't remember offhand what the voltage was
5) I've replaced both relays
6) Condenser fan comes on
7) A/C switch on the heater control panel works, at least to turn the condenser fan on and off

 

[RonJ]

Put in new relays. Condenser fan coming on, and the engine idles down a couple of hundred rpm when I turn it on, but I can't feel the compressor kicking in and the air didn't seem to be getting cold at all, although I only ran it for a few minutes as I was kind of in a hurry

First take the time to verify that the A/C still does blow cold. If you do the fan and clutch relay switch, does the compressor now engage?

To recap, this is what I've tested and tried...
1) If I jump power from the interior fan switch to the compressor, the compressor comes on.

Does the A/C blow cold when you do this?

2) I've replaced the ECU 3) ECU receiving voltage from the compressor clutch relay

The ECU does not seem to receive a signal from the control panel because the idle speed should increase when the A/C button is pushed.

4) Sending voltage to the heater control panel, though I can't remember offhand what the voltage was

Not sure what this test was.

5) I've replaced both relays

With known good relays?

 

[floralvikings]

When the compressor was on it blew snowballs

I haven't switched the relays yet, going out to try that shortly. The relays I got were working when they were pulled from the car.

What wire should I check to see if the ECU is receiving signal from the control panel?

 

[RonJ]

With the clutch relay removed and the key in ON(II), do you measure battery voltage at the Blk/Yel wire terminal of the clutch relay receptacle?

The signal that the ECU receives from the control panel is ground for a small reference voltage (5V) on the Blu/Red wire.