Mourtzy

Hey guys.
Having trouble with the blower motor.
We've pretty much tried everything. Jumping the motor to the batt, it works fine. Bridged the gap with the transistor, and that's not it either. We've found out that there is no power getting to the transistor, so the only thing I can think of is the relay.
Yes, we've checked the fuses too haha!
So yea, anyone know where the blower motor relay is on an 05 EM2? Thanks guys!
If possible, a quick response would be greatly appreciated as I live in Canada and it's getting cold REAL fast! I need HEAT!!!! Haha!

gearbox

iTrader: (95)

should be in the fuse box by the battery? #12 heater motor. its a small box next to the group of 9 small fuses. its the only small box directly next to the FI ECU #6 fuse that you use to reset the ecu. see that lil box next to the circled fuse? you need to replace it lol

right above where i wrote 'fi ecu' its that clear square box with a 40 on it. if you cant find a new one just yet, you can swap it with the one right next to it that also says 40 (but then goodbye power windows, which i guess would work better for you).

Mourtzy

Hmm. See we checked that one and swapped it with another one, but still no go... I called Honda and they said that my car doesn't have a blower motor relay???
All I know is that the motor does work, and that we jumped it to the battery and it turned on. But there is no power getting to this clip:

EDIT: Pic too small lol.
New pic -

CraigW

iTrader: (1)

The "blower motor relay" is in the under hood box. iirc it is the big metal cased one ??

The BLU/WHT lead to the blower motor would have +12volts present if the fuse and the relay are working. The transistor provides the ground path to operate the fan.

By chance does the fan spin for a very short time when turned on, then stop ??

Mourtzy

Ok, good to know. It's that HUGE metal one!? Wow lol.
And the grounds do work. The fans don't turn on at all, and there is no power getting to the BLU/WHT wires at all.

gearbox

iTrader: (95)

might be a broken wire then.

Mourtzy

Wires are good man. I just bought a relay today, it'll be in tomorrow. I'll keep you guys posted and we'll see what happens.

gearbox

iTrader: (95)

which relay? did you check ALL the fuses?

Mourtzy

UPDATE. Ok the relay that we thought was bad is called the blower motor relay. It DOES exist, trust me. It's that massive, metallic relay in the fuse box under the hood. We thought that it was the problem however, we jumped the grounds and it clicked into place, signifying that it's working.
THIS means that I am not getting power from my fuse box under the dash, to the relay under the hood. The fuses are good, but we think it's the wire that goes from the under dash fuse box, to the under hood relay.. It's gonna take some work to find where this connection is lost. I'll keep in touch with you guys. This is a really unusual problem.

Mourtzy

Ps. Thinkin of doing a write up of potential problems with blower motor.... Just due to the fact that I've literally tried everything haha!

CraigW

iTrader: (1)

Looks like there is a small fuse involved fuse #14 under dash box. Is for the relays coil circuit.

The relay coil should be powered any time key is on.

lazlong

Do a continuity test on the wire to see if it's bad.

gearbox

iTrader: (95)

suddenly my broken wire suggestion sounds good lol

lazlong

Ahhh, the humbleness. lol

Mourtzy

Haha you got me man!
We thought it was the relay but in turn, it was the wire
But yea, it says that #14 under the dash is power mirrors, I saw that too. That fuse is good tho, in fact, they're all good. I seriously think it's the wire now. There should be power to the blower motor relay as soon as the ignition is turned on according to the wiring diagram. And there's not, although the ground for the relay does work. So if it's not that wire I'm stumped...

CraigW

iTrader: (1)

So your relay coil is not engaging when key is on ??

Pin 2 is ignition switched 12volts through fuse 14.

Pin 1 is direct to ground.

^^^ These 2 are for the relays coil circuit.


Pin 3 is constant 12 volts through the large fuse

Pin 4 is the relay switched 12 volts going to blower (BLU/WHT)

^^ These 2 are for the relays switch circuit.


With the relay out of the box out all of these points will have easy access with a meter or test light.

Mourtzy

Yea pin 2 is the one with no power. Yet the fuse is good.
So the wire has lost connection somewhere I'm guessin

Mourtzy

Also, fuse #14 says it's for power mirrors in my manual.... But you're right, it says #14 in the service manual so I'm not sure.

CraigW

iTrader: (1)

It list fuse # 14 as compressor and condensor fan relays, blower fan relay, heater control unit- panel, power mirrors, radiator fan relay, recirc control motor & rear defroster relay.

(quoted from svc manual)

You might check to see if any of those items are inop.

The wire color between the fuse and relay coil is BLK/YEL.

Mourtzy

Yea I definitely will give those a look. And yea, that's the wire that I think is disconnected somewhere. I'll be taking a look at it this weekend. For now, I just jumped the relay to the battery haha! It may not look the greatest but it works for now

JoelQ

Thought I'd revive this thread as I appear to be having a similar problem, but this time on an 8th gen Civic.

Were you able to find a solution to your problem?

The symptom I am having is intermittent operation of the A/C blower motor. I've replaced the blower motor transistor and jumpered the blower motor with 12v to prove that it works, and it does.

Doing the A/C self diags while the problem is happening gives results in 6 blinks of the recirc light. When the problem isn't happening the self diags tests clean.

Hoping to find some other ideas to test.

Thanks!

Mourtzy

Hey! Yea I was able to find a solution. It actually turned out to be a yellow wire that was severed right before the fire wall. This wire connected to the blower motor relay, and gave it power when the ignition was turned on. If the relay has no power, it can't engage and start the fans. So that was the problem with my car. I just looked for the yellow wires near the firewall on the passenger side and found that it was cut. Then just soldered it back together and taped it up.
Hope that helps!

bugout57

Hello, All. I have been reading this thread today as I've been troubleshooting my lack of heater blower and I am now totally confused ( not an unusual state for me lol).
I have 12v at the blu/wht wire and a good grnd at blu/blk and the fan runs fine when jumped directly to 12v on the bench, but nothing when it is in car. Double checked the blu/wht and grnd with key on acc. and fan switch on all positions, still 12v but no fan, I don't get it!
Any help would be appreciated,
Sam

CraigW

iTrader: (1)

^^ if you have 12 volts on the blower motors BLU/WHT you may have a problem with the transistor unit. Turn the fan switch on and look down in on the blower fan motor, while watching turn the ignition to II and see if the fan runs for a short second then stops.

The transistor circuit provides the grounding (and speed control ) of the blower motor.

bugout57

Thanks, CraigW, I just tested as you said and that is exactly what it did. Fan moved just a little bit and stopped. Where exactly is the transistor unit and is that a factory only part or should a good parts house have one or access to one? I need to get this fixed before we get another snow!
Thanks again for all your help, this forum is a life saver.

CraigW

iTrader: (1)

https://www.civicforums.com/forums/3...ght=transistor

You may be able to locate the TCO that is open and repair it or you can order new transistor and replace it. Make sure you cabin filter is not plugged.

bugout57

Yeah, I found the transistor, I think, It has 4 male terminals and the back (inside of the duct) looks like the back of a power amp (several aluminum plates) DENSO pn# 077800-0682, got it removed and ordered one from NAPA, nobody around here has one in stock. The cabin filter is only 3 mo. old and doesnt look bad but I should probably put in a new set just to be safe. This transistor is not cheap dont want to replace it again anytime soon! Thanks again for all the help.
Sam

CraigW

iTrader: (1)

3 months would be fine, I go 25k miles.

Guess I better be right on that diag after ordering one, I would have tried to fix your original ( A TCO is a thermal fuse that opens at a certain temperature) some who have not changed the filter have had them open.

bugout57

Well, I dont know how to test it, it is a sealed unit with nothing exposed but the male connectors and the aluminum plate things, no reset button or anything, unless that is a different component? I'm not much of an electrician, so this stuff is all Japanese to me. (pun intended, lol). Do the TCO's reside inside the Transistor? Or are they a separate component residing somewhere else? I can always cancel my order if there is a better way to fix it. Thanks,
Sam

CraigW

iTrader: (1)

To the best of my knowledge (common problem for 7th gens) never messed with mine though.

The TCO has a 114 degree C rating... this is what I read and never got a 100% confirmation. It is a silver .25-.375" x .25" round tube with wire leads at each end. The part is not expensive but locating one quickly and cheaply could be a challenge.