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Technical => Electrical Tech => Topic started by: tbolt64 on December 02, 2014, 02:58:30 PM

Title: Ground issue???
Post by: tbolt64 on December 02, 2014, 02:58:30 PM
Has anyone ever run across a problem where the "door ajar" light burns dimly and the blower motor still blows even when the key switch is turned off and on occasion the power door locks try to lock the door like the switch is on?

This just recently cropped up on my '84 V8 Elan.

I am checking the dash ground shortly.

I checked the EVTM and it says everything should ground there, but I was wondering if anything grounded through the ECM, which I took out because of my recent carb conversion.

Thanks,
Drew
Title: Ground issue???
Post by: tbolt64 on December 02, 2014, 03:05:44 PM
I think I found it! \

The ground was bolted to the back of the radio on a big clip thingy, and I didn't have the clip slid into place just right.

I think I'm going to re-attach this to the dash steel instead of the clip thingy.
Title: Ground issue???
Post by: thunderjet302 on December 02, 2014, 06:06:27 PM
Just wondering but how does your car's ignition switch look?
Title: Ground issue???
Post by: tbolt64 on December 02, 2014, 07:11:59 PM
No, that ground didn't seem to do it.

Thunderjet, I assume you are referring to the big mechanical switch, not the lock cylinder. The original is still installed with those obnoxious rivets, but it doeaent have any slop. I wondered about that too, but I figured the half lit "door ajar" indicator lamp when no doors were ajar and only when the switch was off would indicate some sort of grounding problem.
Title: Ground issue???
Post by: Haystack on December 02, 2014, 07:35:10 PM
X2 on the ignition switch.My car doesn't have the system centry option so i don't have a door ajar light, but im pretty sure it only lights up with the key on.
Title: Ground issue???
Post by: thunderjet302 on December 02, 2014, 08:31:01 PM
Quote from: tbolt64;441262
No, that ground didn't seem to do it.

Thunderjet, I assume you are referring to the big mechanical switch, not the lock cylinder. The original is still installed with those obnoxious rivets, but it doeaent have any slop. I wondered about that too, but I figured the half lit "door ajar" indicator lamp when no doors were ajar and only when the switch was off would indicate some sort of grounding problem.

Your car still has the factory ignition switch? If so change it out. It should solve your problem. Plus it's a fire hazard.
Title: Ground issue???
Post by: tbolt64 on December 02, 2014, 10:29:59 PM
Very good... I had wondered about the switch, I guess drilling out the rivets in the morning will be the order of the day.
Title: Ground issue???
Post by: Haystack on December 02, 2014, 10:50:23 PM
They should be screws that the head was broken off as an anti theft measure. Try hitting them with a punch nd chisel to see if they spin, or cut a slot with a dremel and see if you can get a flathead in there.
Title: Ground issue???
Post by: Thunder Chicken on December 03, 2014, 09:29:06 AM
The ones in all my cars were tamper-resistant torx screws. A torx bit with a hole in it fits.
Title: Ground issue???
Post by: tbolt64 on December 03, 2014, 12:45:56 PM
I changed the switch, but that didn't fix the problem... Back to the drawing board.
Title: Ground issue???
Post by: EricCoolCats on December 03, 2014, 01:17:45 PM
How did the harness look? Any burned wires or melted plastic?
Title: Ground issue???
Post by: tbolt64 on December 03, 2014, 01:21:39 PM
Looked good, going to the ignition switch that is...

Could I have a bad diode in the alternator, thus getting "reverse" draw back through the blower switch (as the switch ultimately hooks to the diode?
Title: Ground issue???
Post by: softtouch on December 04, 2014, 03:21:04 PM
Try unplugging the cables from the keyless entry module. EVTM pages 101-103.
Does the door ajar light turn off?
Title: Ground issue???
Post by: tbolt64 on December 04, 2014, 11:52:54 PM
Yes the light goes off, I am currently on my 7am to 7pm swing... I will give it a shot on Monday, though.

The alternator is not the problem, however...
Title: Ground issue???
Post by: Stealth on December 05, 2014, 12:10:09 PM
Does the car have Automatic Climate Control? You mentioned the blower runs when it should not. Just thinking there could be some sort of problem in the solid state blower speed controller. It is below or behind the glove box, you might try unplugging it.
Title: Ground issue???
Post by: CoogarXR on December 05, 2014, 12:34:21 PM
Do you have an aftermarket radio installed?
Title: Ground issue???
Post by: softtouch on December 05, 2014, 01:52:44 PM
Quote from: Stealth;441327
Does the car have Automatic Climate Control? You mentioned the blower runs when it should not. Just thinking there could be some sort of problem in the solid state blower speed controller. It is below or behind the glove box, you might try unplugging it.
Good idea, but the EVTM shows the 84 still has the mechanical ATC and not EATC.
Title: Ground issue???
Post by: softtouch on December 05, 2014, 02:15:05 PM
There are 5 connectors behind the panel you took off to remove the EEC computer. Don't know how many you may have messed with.
Pages are 84 EVTM pages.

C43 3pin (page 43)- T/LG D Fuel pump relay coil ground (EEC pin 22) /  R  Hot with key on to fuel pump relay coil. /  Y Hot at all times to fuel pump relay.

C284 2pin (page 155)- DB/LG Hot in run from ATC function switch to thermal blower lockout switch / O  Lockout switch to blower motor.

C252 2pin (page 119)- Y  Hot at all times to rear window defrost relay /  GY/Y to rear window defroster.

C373 1pin (page 101)- P/Y With trunk release pushed, hot in Accy or Run to trunk release AND KEYLESS ENTRY MODULE pin 7.

C252 4pin (page 80 & 81)- LG/Y Hot at all times to vanity and map lights. /  BK/LB dome light.
  Pages (131 & 132)- DG/O & W/LG H to RH door speaker.

You say the blower runs with the key off. If it is running with the ATC function selector in off, the following may be possible.
C284 and C252 are both 2 pin connectors. If they got reverse connected it may be possible to have the C284 Yellow hot wire connected to C 252 Orange wire to the blower motor.
The thermal blower lockout switch is on one of the heater hoses. Any chance the orange or dark blue/light green wires there got crossed up with a hot wire?

You say the door ajar light staying on dimly, goes away when you unplug the cables to the Keyless Entry module.
The door ajar Switches (page 99) put ground on the ajar light when a door is open. They also put ground on pin 14 of the keyless entry module. When the doors are closed, keyless entry module pin 14 is providing a partial or resistive ground to the light.

The keyless entry module (page 101) also controls the door locks which you say are acting strange.
Sounds like the module is either bad or some wiring changes you made are causing it to be erratic.
 One thing I notice, the trunk release switch puts voltage on pin 7 of the module. When the release is not pushed, pin 7 should have ground through the release solenoid. Check if the trunk release works to rule this out as a possible cause of the problem.

Also the door ajar switches are on the door latch inside the door, not the door jamb dome light switches.
Title: Ground issue???
Post by: tbolt64 on December 05, 2014, 05:06:28 PM
The trunk release works.

No, I do not have an aftermarket radio... and I would love to find another "good" Ford Premium sound radio to replace mine, as the LED that lights the LCD has burnt out.

softtouch: I miss-read your post earlier, I have not attempted to unplug the keyless entry module yet. I will try it as soon as I get a chance. I will also double check the 2 wire connectors, but of the connectors in the kick panel, the only one I recall disturbing was the fuel pump wires (I had to ground the tan and light green wire for the fuel pumps to work without the computer).

My car does have the automatic temp control and it has had some issues in the past before the conversion... The blower has never worked on the "floor" setting no matter how hot or cold the coolant is. I read about the cause of that problem in the EVTM.
Title: Ground issue???
Post by: Trinom on December 05, 2014, 06:21:01 PM
Factory radio doesn't have LED backlight for LCD, it uses small 0,5W incandescent bulb. You can buy them very cheaply from dealextreme - http://www.dx.com/p/0-56w-indicator-yellow-light-bulbs-for-car-audio-system-5-pack-47983#.VIJAqMlARwE .
Title: Ground issue???
Post by: tbolt64 on December 05, 2014, 06:32:06 PM
Well, that a good to know... The 194 looking bulb that lights everything else does work, just not the LCD.
Title: Ground issue???
Post by: Trinom on December 05, 2014, 06:40:58 PM
It's quite long time since I restored my spare radio, but I think, there are those small bulbs mentioned in my last post (incl. link). Maybe a bit bigger 1.2W bulb, but definitely not 194. Open it and take a look (and send a photo).
Title: Ground issue???
Post by: tbolt64 on December 08, 2014, 02:34:44 PM
The keyless entry module seems to have cured the door ajar light and the self locking doors, as the power door locks have been deactivated with the module unplugged. The blower motor is still getting 12V when the key is off, so I guess I will keep looking for that...
Title: Ground issue???
Post by: softtouch on December 08, 2014, 08:00:41 PM
Quote from: tbolt64;441422
The keyless entry module seems to have cured the door ajar light and the self locking doors, as the power door locks have been deactivated with the module unplugged. The blower motor is still getting 12V when the key is off, so I guess I will keep looking for that...
Will switching the ATC function Selector to OFF, turn the blower off?
Title: Ground issue???
Post by: tbolt64 on December 09, 2014, 09:29:56 AM
Yes it does... I was just trying to make it "right".

Is there anyway of finding a functioning keyless entry module?

I guess, that means Im asking if anyone has one for sale?
Title: Ground issue???
Post by: softtouch on December 09, 2014, 01:24:42 PM
Fuse 9 is the power source for the function switch. Pull fuse 5 (page 16 & 18) to see if there is a back-feed to fuse 9 from the fuse 5 circuit.
Also do you know whether the car has Trailer Tow feature?

edit: Checking further, I see that fuse 5 goes to the Keyless Entry module. Have you checked to see if you still have the blower problem with the module disconnected?