DelSolDon

My wife's '93 Civic DX sedan hasn't been starting lately. It isn't all the time, but it happens after it has been sitting for a while (at least overnight). It acts like a drained battery because all interior lights are dim, and it takes a while for the battery to charge up enough thru a jump charge to start the car.

It has a new battery, all grounds are there (even replaced the one that was questionable), new starter, and the alternator tested out at 70 amps.

It has had an issue with the heater controls staying on after the car is turned off. For a while, all I would have to do is make sure that the fan was turned off and none of the lights were illuminated, but that has since changed. Then I tried disconnecting the wiring harness that leads to the heater controls while it sat overnight... same problem. So then, when I replaced the battery with a brand new one, I hooked up the negative terminal, then just touched the positive terminal to the post. It sparked a little and I heard a relay clicking in the underhood fuse box. It was the heater motor relay, so I took it out, touched the positive cable to the post again and no spark. Got in the car, tried to start it and still nothing. I had to jump the car initially to start it, but for now, it seems to hold the charge overnight.

However, I need to figure out what is wrong with the heater controls so that my wife doesn't freeze during the upcoming winter. Personally, I have narrowed it down to a problem with the underhood fuse box or a problem with the ignition switch. If you have any info to back either of these assumptions up, let me know... or if you think it's something totally different, let me know.

Cliffs notes: battery won't hold charge, seems to have a slow current draw, narrowed down to "heater motor relay", allows current to relay (inside underhood fuse box) when key is out of ignition. fuse box, ignition switch, or something else?

thanks

DelSolDon

according to the Helms wiring diagram, the positive power from the battery goes thru the underhood fuse box where it splits off to:
-the ignition switch and then on to the heater control panel on the dash
and
-directly to the heater motor relay that goes on to the blower motor and fan speed switch

here are the circuit diagrams of what i'm talking about:


*click on thumbnail to see full size*

DelSolDon

alright, it looks like i'm alone in this battle. i did some more thinking and i unplugged the wiring harness to the ignition switch completely and i am still getting constant power to the heater controls, so i'm pretty damn sure that it has to be something screwy with the underhood fuse box. although, it could be something hard-wired somewhere in the car to be causing this. i'm hoping it's just the fuse box since i can't find anything hard-wired in the car aside from VTEC.


Modified by DelSolDon at 11:57 AM 10/31/2007

Duane_in_Japan

I am an AC specialist and I know this system but I need to get the facts straight, with the key out and even the ignition switch disconnected (are you sure you got the correct harness) the blower motor relay still has power? The ignition switch gives power to the coil portion of the relay, with the ignition switch unplugged, and you remove and insert the relay to the fuse box, it should not click, does it please.

Does the blower motor work in all speeds and it does not work when the fan switch is in the off position. When it is on does it seem to blow at regular strength. With the fan on and you pull the relay, does the motor die?

This relay is powered 100% of the time the key is on even when the car is not running, its a strange set up from the normal I know, so understand this is normal, the fan has power standing by at the fan just looking for a ground through the fan speed switch.

The under dash fuse #13 7.5Amp controls the relay coil half and several other items in the AC system. Fuse #37 30Amp underhood fuse panel controls power to the fan blower relay switch half and the blower fan motor itself.

That is enough for now until you can give a tadbit more info please.

Relic1

at first I was thinking the ignition switch, but since you unplugged it and it still had power, it has to be something shorted or jumpered along the black/yellow wire from the underdash fuse box.


check fuse #13...


pull the fuse and see if the power goes away, if it does there is a problem before the fuse box, if it doesn't go away then it's after the fuse box.

DelSolDon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Duane_in_Japan &raquo;</TD></TR><TR><TD CLASS="quote">I am an AC specialist and I know this system but I need to get the facts straight, with the key out and even the ignition switch disconnected (are you sure you got the correct harness) the blower motor relay still has power? The ignition switch gives power to the coil portion of the relay, with the ignition switch unplugged, and you remove and insert the relay to the fuse box, it should not click, does it please.

with the key out, the ignition switch harness disconnected, and the heater motor relay out of the underhood fuse box... i am still getting power to the heater controls in the dash. they will illuminate the lights, but the blower motor does not work because the relay is removed. i haven't tried to insert the relay to see if it clicks with the ignition switch harness unplugged though.

Does the blower motor work in all speeds and it does not work when the fan switch is in the off position. When it is on does it seem to blow at regular strength. With the fan on and you pull the relay, does the motor die?

blower motor does work in all speeds as normal when the relay is in place. yes, the fan does die when the relay is pulled out of the underhood fuse box.

This relay is powered 100% of the time the key is on even when the car is not running, its a strange set up from the normal I know, so understand this is normal, the fan has power standing by at the fan just looking for a ground through the fan speed switch.

that is interesting and makes some sense as to what i've seen.

The under dash fuse #13 7.5Amp controls the relay coil half and several other items in the AC system. Fuse #37 30Amp underhood fuse panel controls power to the fan blower relay switch half and the blower fan motor itself.

That is enough for now until you can give a tadbit more info please.</TD></TR></TABLE>

thanks for the help

DelSolDon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">at first I was thinking the ignition switch, but since you unplugged it and it still had power, it has to be something shorted or jumpered along the black/yellow wire from the underdash fuse box.

check fuse #13...

pull the fuse and see if the power goes away, if it does there is a problem before the fuse box, if it doesn't go away then it's after the fuse box.</TD></TR></TABLE>

i pulled the 7.5A fuse for "RR DEF RLY/ HEATER MOTOR RLY/ COOLING FAN MOTOR RLY" and i am still getting constant power with the key out at the black/yellow wire in the wiring harness that gets plugged into the dash heater control harness. i plugged the harnesses back together and i am still lighting up the lights with the key out.

Duane_in_Japan

Your original post was a bit vague on the lights still being on with the heater control panel, be right back with more info. Back lighting or little switch green LEDs or both please.

DelSolDon

it is just the little green LEDs that light up.

Duane_in_Japan

It appears that we are down to the root of the problem, the green LEDs are each individually controlled by their very own push button switch, face, feet, defrost, combo, recirc, vent, main power. If the LEDs are on then the control head has to be shorted out, these lights can only be on a couple at a time as though that part of the system was actually turned on such as, Main Power, Recirculate and Defrost, all the other LEDs MUST be off.

What do you think, if the main power switch is off, no LEDs should be on. How many and which ones are on.

The dimming circuit in the control head gets its power from the blk / yel wire fuse #13 via the ignition switch. Waiting to see which LEDs are on, also are those individual buttons pushed in.

DelSolDon

it only lights the LED when the button is pressed in, but it does it while the key is out of the ignition. and yes, i get power at the black/yellow wire when the fuse #13 is removed and also when the ignition switch is unplugged.

Duane_in_Japan

OK, this is normal with a known short to the Blk / Yel wire. If the heater fan switch is off I am guessing that the main power LED does not light up when the main power switch is turned on, its power and ground are different than the other LEDs.

I just helped a '97 Acura Integra last week, I have the diagram in fron to me for the AC System only, fuse #13 goes to 7 different area of the AC System alone and I do not YET know how many places throughout the entire car.

Radiator Fan Relay Coil, Blower Motor Relay Coil, AC Compressor Relay Coil, AC Main Control Panel Dimming Circuit, Mode Door Control Motor, Recirc / Fresh Door Control Motor, and AC Thermostat down near the Evaperator case, now that rings a bell.

The AC thermostat controls the power to the main AC Switch and its LED. How do we look there.

I am sorry brother, its 2 AM here, more later please from me, maybe Relic1 will get back on. I have a huge database but that computer is doing some automated work right now.

DelSolDon

sounds good so far, also you should probably know that the car USED to have A/C. the compressor, condensor, and lines were removed, but a lot of the wiring and relays associated with the A/C is still there. i did not do the removal, so i don't know for sure right now what is all there and what isn't.

thank you very much for the help.

Duane_in_Japan

Can you please take some pics of this stuff and how you are testing for power with pics of the probes please, volt meter or test light please, I am working on a huge project with the Honda AC System please, this will be a huge help although this problem may never show up again. Close up of the wire colors and pin configuration please, more instructions to come if you dont mind sir.

More brain gas here, AC Diode shorted?, thermostat shorted, later.

Relic1

I'll throw a few more ideas on the fire...

does your rear defrost have power all the time?

what happens if you disconnect the grey plug located behind the right headlight? (8 pin plug)

DelSolDon

i am testing for power with a 12volt buzzer w/ one pos+ and one neg- lead on it. sorry, but i'm working at home and not at my garage where i have my multimeter. pictures of the harnesses and where i am getting power is from the black/yellow wire here:





Relic1: i unplugged the 8-pin grey plug behind the headlight and everything seems to act as normal. is this just the A/C component harness? oh, and the rear defrost is pretty much gone from the rear window (from previous tint that was taken off), so i just removed the rear defrost relay.

Duane_in_Japan

I went ahead and stayed up, looked at database, only one issue after an accident was to repair the harness in the wheel well area.

Thanks for the pics, would it be ok to get the other angles from the wire side showing the wire colors going into the pin from the back please. Can we go over this other connector (8 pin by headlight) too and figure out what it is.

Are you going to have radiator fan and blower fan now, everything else is useless except the head unit. Can you take some pics of reassembly and screw locations, if this is all too much then its great so far thanks. Start it up and make sure the radiator fan works too.

Now I have to go, more tomorrow.

Relic1, would you mind explaining what you found please.

DelSolDon

so far so good with the disconnection of the 8-pin connector. everything associated with the heater controls works as it should. the LEDs come on with ignition and go off when the car is shut off, the blower works just as it should. *knocks on wood* it all seems fixed. i answered my own question and it IS just the A/C components in the 8-pin plug behind the right side headlight.

the previous owner just unplugged all of the electrical connections to the A/C compressor and condenser fan along with just having what look to be 2 large relays just laying there also. most of it was ziptied up, but it saw a lot of weather and you could tell there was pretty heavy corrosion at least in the end of the exposed plugs.

i didn't have enough time before the wife had to take the car to a job interview to make sure that the radiator fan comes on. i will update with that info ASAP.

Relic1

that connector is to the A/C, C218

pins:
1 - yellow/white - condensor fan relay signal to pressure switch and thermo switch
2 - blue/red - A/C request from ECU
3 - black/red - A/C clutch control from ECU
4
5 - black/yellow - switched power to A/C compressor and A/C fan
6 - white - hot at all times
7
8

(coudln't find 4/7/8)

pins 5 & 6 are the signal and feed for a relay (pins 1&2)

as far as I could tell that is the only harness plug under the hood of a civic with A/C that has the line you're having problems with and a constant power line.
It was a long shot to mention it, but I thought it was worth a shot.

**edited the wire colors**


Modified by Relic1 at 3:15 PM 11/2/2007

DelSolDon

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Relic1 &raquo;</TD></TR><TR><TD CLASS="quote">It was a long shot to mention it, but I thought it was worth a shot.</TD></TR></TABLE>

and i'm glad you mentioned it, THANK YOU and here's one to Duane_in_Japan

DelSolDon

and here are the labeled wires on that harness Duane:

Relic1

because I'm avoiding actual work today...
that connector is C727

1 - blue/white - Med1 blower motor resistor signal
2 - Not used
3 - blue - low blower motor resistor signal
4 - black/yellow - A/C indicator power (12V in run)
5 - red - dimmer
6 - green/red - recirc signal
7 - green/white - fresh air signal
8 - blue/yellow - Med2 blower motor resistor signal
9 - not used
10 - black - ground (G201)
11 - blue/black - high blower motor signal
12 - red/black - park lamps
13 - blue/red - thermo switch to A/C switch (ground feed from A/C switch)
14 - black - ground (G201)

DelSolDon

and the radiator fan comes on like normal

thanks again guys

Duane_in_Japan

Thank both of you too for helping with my project and going the extra mile on the labelling. The two large relays should be the condesor fan relay and the compressor clutch relay.

I believe that on your car there is only one temp switch A to turn on the radiator fan, some vehicles have a second temp sw B and it will turn on the condensor fan for extra cooling due to slight over heating.

Are you saying the 8 pin connector was or was not plugged in, either way, it was heavily corroded shorting pins 5 and 6 together, since pin 5 is hot at all times, it was feeding the Blk / Yel wire while fuse #13 and the entire ignition switch circuit was removed from the car.

The White wire at connector C218 is for the two large relay switches that actually power the condensor fan motor and the compressor clutch from UH Fuse #35 30Amps. Eventualy I believe that we would have pulled this fuse and the problem would have disappeared, even with C218 still plugged in, now on your car with the AC removed, this fuse has no further purpose.

I am going to guess that with fuse #13 installed, a shorted C218, and a removed UH Fuse #35, that both terminals of UH Fuse block will be hot, the cold side will be backfed by Fuse #13 due to the short in C218. Pulling Fuse #13 will allow the cold side of UH Fuse #35 block to go cold again.

Your info on the 8 pin connector is off just a touch and if you can verify the other colors (4/7/8), I should have it all figured out and will repost the correct pin out info. The three missing pieces (4/7/8) are for the Condensor Fan Relay Coil and Switch and then the Compressor Clutch signal itself from the Compressor Relay Switch. I also believe that the Pressure Switch (w/AC Thermo & AC Diode in its circuit, I knew it) was located out front at or near the Receiver / Drier and its wires went through C218 also. EDIT: Only the first sentence is correct, some colors need reversed, I now believe that the uncolored pins (4/7/8) are not used at all. The wireing for the items mentioned in this paragraph are split off from some components after C218.

Thats it, mission complete, reinstall ignition switch and fuse #13, either pull C218 or pull UH Fuse #35 30Amp to remove power to the short circuit EDIT: AFTER C218 between the Wht wire and the Blk / Yel wire, EDIT: at the two un-needed relays hiding behind the bumper

Any more photos of the other components, NO. This was a huge plus, thanks again. Out of curiosity, was C218 anywhere near that battery (acid fumes).


Modified by Duane_in_Japan at 3:49 AM 11/3/2007


Modified by Duane_in_Japan at 3:52 AM 11/3/2007

DelSolDon

the 8-pin connector was plugged in and the part of the harness that would connect to it and (normally) run to the A/C components was just zip-tied behind my front bumper pretty well exposed to the elements.

the connector C218 is not near the battery, and there wasn't really any problem with C218, just the plugs and relays after it.