View Full Version : 81 Accord: When I turn on the AC the engine fans stop

07-26-2012, 04:35 PM
When I turn on the AC the engine fans stop. This isn't normal. We took the car to an A/C shop in Sherman Oaks and the first step, they said, was replacing a bad relay. But they called and said they need to find the relay first, as it's discontinued from Honda. Does anyone know what relay they're talking about?

07-26-2012, 06:36 PM
Yes normally turning on the AC will activate the cooling fans if not already operating so I guess faulty relay might stop the fans operating even if the engine wants them.
Even though AC was offered standard upon the upper spec. models it was also available to dealers as a kit for dealer installation if buyers wanted that option, so its wiring harness was separate from that of the car and a relay can be found upon that harness bolted to the front of the passenger side strut tower. Hopefully that's the one.

Looking up one online partbook provides:
part #15
39400-657-672 RELAY ASSY., FAN (056700-3510)(DENSO)
Replaced by: N056700-3510 JPN 2 $15.82 $11.47
or N056700-3510 RELAY, AIR (056700-3510) (DENSO) (NOT AVAILABLE)
(not that I have any preferences for that supplier -just easy to look up/remember)

I would have thought such a relay would be pretty generic?
Relays are usually very frustrating when they fail as the often do so intermittently.

Rendon LX-i
07-26-2012, 06:44 PM
i might have laying around. i took my working ac system out while back.

07-26-2012, 08:06 PM
Thanks guys, they're calling me tomorrow about this. If they can't get it locally I'll have to order it online and take the car there again after the part actually arrives. I'll double-check the part with them tomorrow and try to get it from hondapartsnow.com if all else fails. There's also one on eBay.

07-26-2012, 08:07 PM
i might have laying around. i took my working ac system out while back.

What did you put in its place?? Anyway, I'll know more tomorrow. Thanks!

Rendon LX-i
07-27-2012, 10:58 AM
i just disconnect the harness. Is on the left side. it connects the the pressure switch and fans and dryer.

07-28-2012, 01:12 AM
I'm getting some confusing info from the shop. Seems the mechanic and the office guy don't communicate very well. Anyway, apparently they got the relay and now they're saying I have a weird ignition switch. It looks like the previous owner did some work on the inner electrical system, I don't know why. They're finding all these wires that shouldn't be there.

What they said was that upon bypassing the switch the A/C actually works and wasn't broken. But that if they don't swap the ignition switch, turning on the A/C will cause the blower motor to stop and my engine will overheat.

The fact that this is already run me $160, just for a diagnostic, is getting to me, I don't know how competent these guys are but I'm not using them again after this.

There used to be a $1600 stereo system in there, placed by the previous owner, but some Melon Farmer broke into our building's garage and stole it. I'm wondering if the custom stereo installation was why there's so many extra wires. I can't imagine why this would be.

07-28-2012, 09:34 PM
Wow that was $327.00. At least the A/C works now and the fans engage when needed.

So far I've spent much more on the car than the original purchase price but I've learned a few lessons.

One of which was right in the beginning, two years ago: maintenance at the Honda dealership is useless. They charged a lot and did NOTHING.

07-28-2012, 09:51 PM
Sorry to hear about your bad experience. One of the lessons I learned shortly after the one about the dealer being less than helpful is that doing it yourself is the only way to ensure it's done right. Do your own work, you'll be happier and wealthier in the end.

BTW, glad your AC is working again.

07-29-2012, 01:38 AM
Ouch. Another frustrating experience but hopefully It's sorted now, (& will save the engine).
I guess Honda's routing of power through Ignition (& headlamp) switches without relays doesn't help their lifespan, and the Accords wiring harness revisions for '79 & again for '81 make it easier for people to get the wrong part and try to make-it-work improperly, (maybe how it got that way).