Yet another thread about Gate Ajar light

Yes, I ran a search and I know there are five other threads on this topic. I didn't find an answer, so let's start with a clean slate on this one.

My gate ajar light is on, permanently. It takes a while to kill the battery: about 10 days. I removed the passenger-side access cover inside the tailgate and disconnected the "Gate Ajar" switch, and the light stayed on. So, I can't just disconnect the switch and solve this problem. I pulled fuse number 35 (CTS/power locks) and the Gate Ajar light went out, along with my interior lights.

I assume I have to isolate a dead short somewhere and fix it. Does the above information contain any clues are to where to begin the hunt using a volt/ohm meter?

Perhaps poke around with non-contact voltage-detector and see if you can trace anything?

NEXT!

You found the small switch on the lower gate/door latch. If it is not actuating enough, the light will stay on. The arm can get worn, and I believe that if you put a piece of heat shrink tubing over it, that should fix it. Try pushing the arm when you have the switch where you can get at it, to see if it is good. A single Philips screw holds it to the latch.

Would the light not go out if the wires to this switch were disconnected?

To test as described above, should I close the gate and then move the arm a bit more to see if the light goes out?

That would be a good start.

This is getting strange. If I open the gate in door mode, the Gate Ajar light goes out and the cargo lights come on with their switches in the "off" setting. Depress the Gate Ajar switch manually, and the Gate Ajar light on the dash comes back on and the cargo lights go out. Disconnect the Gate Ajar switch and the light on the dash stays on.

Is the Gate Ajar switch normally open or normally closed, and is it switching hot or ground?

Were these cars wired by British Leyland???

They were wired by LUCAS, not British Leyland...The reason Brits like warm beer is because of LUCAS...they built the refrigerators.

There may be an open in the circuit.

The manual says; disconnect the tailgate ajar switch connector, connect a fused jumper from connector terminal A to ground...are the courtesy lamps on?

Yes; check CKT 150 for an open between tailgate ajar switch and (Splice) S314, also check CKT 146 between S211 and S319 with SEO wagons equipped with a U11 instrument cluster.
If OK, replace the tailgate ajar switch.

No; check CKT 146 for an open between inoperative lamps and tailgate ajar switch.
If OK replace rear courtesy/reading lamps.

I realize that this is probably not enough information, but that is what is in the FSM for a 92.

The switch is normally closed when the gate is open according to the wiring diagram. It switches ground. Pin A is from the lights, and pin B goes to ground.

OK, if I connect pins A and B at the connector, then I have removed the switch from the circuit, and will have the equivalent of a properly functioning switch in the closed position, but without the complicating factor of a switch, correct?

Then all I have to chase down is a possible circuit glitch in the rear cargo lamps. On the other hand, if they work correctly, then I'm done. I can easily live with one less idiot light.

I would have to experiment with it to be sure.

How does the gate ajar switch work with the rear door light and  light push button switches?

My gate ajar seems to work sometimes, but the lights do their own thing, sometimes they are on, sometimes they are off and pushing the switch results in no logical reaction, sometimes they turn off, sometimes they do not.

I have left the car with them off, and a few hours later they turn themselves on, and have even run down the battery, so I need to understand what is failing.

I don't have a wiring schematic in front of me, but from Fred's description from the FSM (Factory Service Manual), it seems a properly functioning and adjusted switch is open and interrupts the ground when the gate is closed.  When the buttons on the cargo lamps are depressed to the "off" position, opening the gate will also ground the lamps, and they will come on.  Set the cargo lamps to "on" and they should light up even when the gate is closed. The cargo lamps must have 2 ground wires and a "hot", and one of the ground wires is routed through the gate switch, and the other is routed through the button switch on the cargo lamp itself. So, the cargo lamps will come on when they are properly grounded, either by depressing the switch on the cargo lamps, or by opening the gate.

Disclaimer: this is all deduced bits and pieces of information, so I may have it totally screwed up.

Since I don't have a properly functioning example to work with, I need to get the wiring diagram to figure this mess out, but that's my recollection of how things worked on my two previous wagons.   Anyone out there have a wiring schematic for the ass end of this car?

The hack solution (which I am viewing more fondly with every passing day) is to remove the indicator lamp in the dash.  At least then the battery won't go dead, and I can put the gate back together.

That is the correct deduction for the normal function of the gate closed sensor and the cargo bay lights.

I would close the gate (slam it) until the dash light goes off. Then the cargo bay lights should be off. If they are not off, push each switch once (these switches are known to be poor quality, and can break), so the light(s) goes out. That should be the correct switch positions.

If the gate switch uses its arm to make the switch open when you close the gate, you can put a piece of heat shrink tubing on the arm of the sensor switch, and it would push the arm a little more when the gate is closed, to take up for any wear on the arm. I would look into this possibility first.

If the cargo bay light switches do not work properly, replacement is the only option. You can not get a new harness for the switches, or repair the switch itself. I did see where someone found the manufacturer of the switches, and got a pigtail, but I do not know who made them. The switch is made like a Bic retractable pen mechanism.

If the cargo lights are coming on at a random time, it is probably the gate ajar switch. You also have the cargo light switches in the correct position. Any time the gate ajar switch light is on, the cargo bay lights will be on through that circuit, and you will not be able to turn them off.

Ok guys, this is confusing stuff to me.  In the first post, I read that the problem even occurs with a disconnected switch. Am I lost here?
Pete

It's not so confusing when you remember that the switch is only making or breaking a ground connection. The entire car body is a ground. Any short circuit of a component to the car body will result in a complete circuit without overload. Unlike a short of hot wire, this generally won't blow the fuse. If there is a light in the circuit, bingo... it's on.

This, along with the electrocution hazard, is why you don't put a switch on a ground wire in home electrical systems.

I dig the home electrical stuff, no probs there. Just confused about disconecting a switch and still having the problem. A bit like replacing the rear taillight bulb with a wrong one, that mixes up your system to. (i.e. replacing it with the wrong type of bulb)
But, found the cure yet?
Pete

No cure yet. The car is in the garage for the winter, and it's about 2C in there when I get home from work. Friday night I'll crank up the woodstove, which will mean I can complete the "repair" on Saturday. Based on the symptoms thus far, my best guess is a properly functioning gate switch, but a faulty button switch on one of the cargo lights. In one of the combinations of gate open/closed, switch depressed/not, I'm getting one of the cargo lights on, and the other glowing very dimly. I can make the dimly-glowing light either the lamp on the driver or passenger side of the car, depending on the cargo light switch positions.

I have not yet dug into the cargo lamps to see if it's possible to get a VOM probe in there to check continuity between the lamp switches and the connector to the gate switch. This may require a very cold trip to the local Pick and Pull to get some new switches. Ugh. It's cold out there.

Dark Green wire goes to the tailgate switch, Black to ground. Orange is hot at all times. The orange wire goes directly to the light bulbs. Dark green (other side of the bulb) goes directly to the tailgate switch. If the tailgate switch is in the open position, you can check the individual light switches to ground on the same side of the bulb. Check the tailgate switch for operation while you are at it. The gate switch is closed when the gate is open.

It is obvious that your tailgate ajar switch will close, causing the light on the dash to come on. The question is will it open when the gate is closed to break the circuit, and remove the ground for the lights.

Quote :

It is obvious that your tailgate ajar switch will close, causing the light on the dash to come on. The question is will it open when the gate is closed to break the circuit, and remove the ground for the lights.

Ahh... now I see. Dawn comes late in my part of the world.

OK. I have completed the steps outlined in the FSM.
*Gate is securely closed
*Dash light "gate ajar" light is on
*Gate lowered to dropgate position
*Dash light "gate ajar" light is on, cargo lights are off
1. Disconnected the tailgate ajar switch connector
2. Jump wired from connector terminal A to ground
*Cargo lights are on, dash light out

If cargo lights are on, FSM recommends to check for break in connection between the connector and the tailgate ajar switch.

Straightforward enough. In addition, I tried the following:

1. Padded the arm on the tailgate ajar switch in the event that it was not moving sufficiently on closing. No effect on problem.
2. Disconnected tailgate ajar switch connector with gate in dropped position (switch should be "closed" in this status. Checked continuity across terminals A and B. Read no continuity, consistent with open switch or break in wire from connector to switch.

The gate in the gate open position has no affect on the light. The switch should be in the open position, the same position as a closed gate.

I might as well remove the switch and test it outside of the car while I have everything in pieces.

Is there any electrical downside to pulling the instrument panel and removing the bulb for the tailgate ajar signal? I would think that screaming children, wind whistling, or the appearance of a cargo-strewn road in the rearview mirror would be sufficient warning without the complications of this circuitry.

The gate ajar light and cargo bay lights should both be on when the gate is open as a door. You can only turn the cargo bay lights on and off manually is when the gate is closed, and the gate ajar light is out.

If the cargo bay lights are out when you close the gate, and the gate ajar light is on, there is a ground fault in the gate ajar light circuit. Check at connector C405 and C200. C405 is on the left D pillar. C200 is above the accelerator pedal. With the gate closed, disconnect C405. The gate ajar light should go out. If not, you have a ground fault between there and the light in the dash. If it goes out, you have a ground fault between C405 and the gate ajar switch. You could have a pinched wire, or the connector for the gate switch may be faulty. I would look for the pinched wire.

When you jumper from A to ground the dash light should go on, and the cargo bay lights should be on as well. The cargo bay lights are acting correctly, and the gate ajar light is not.

Fred: your patience in this matter is greatly appreciated. To access the connector C405, is it necessary to remove the D pillar cover? If so, I assume there are tricks of the trade to removing the D pillar cover without damaging it. Are there any special tools required?

The connector is accessible by just removing the storage bin panel. It is located about half way down the gate jam, and next to another connector. It should be the one towards the inside of the car, provided someone did not move it. Verify it before disconnecting it.

Success (of a sort)!  Removed the storage bin panel and found four connectors in the approximate location of C405. The uppermost light-gray connector on the outside of the pillar was C405. Disconnecting it shut off the "gate ajar" indicator light, and also disconnected power to the cargo lamps.




No pinched wires found. For now, I'm happy to live without the cargo lamps and indicator light. When it's a bit warmer, I'll remove the interior panels and chase down the fault. It's somewhere between C405 and the connections to the gate ajar switch.

Interesting read folks.

I'm having a *similar* issue with my 94 RMW. I was driving along one day and pulled over at a rest stop for my passenger, and when he opened the passenger door, the 'Gate Ajar' light illuminated and made a buzzing noise. I believe the buzzing was a relay quickly turning on and off.  Upon further investigation, I noticed that all interior lights EXCEPT the dash lights (speedo, climate control, radio work fine) are inoperative; no courtesy foot well lights, no rear view mirror reading lights, no vanity mirror lights, no door lamps, no dome lights, cargo lights, etc..  The power door locks will work only when shifting from park to drive and vice versa, but I cannot lock/unlock with the buttons on any door. When I turned off the ignition and parked the car, the relay would NOT stop buzzing, so my temporary-fix for that was to leave one of the vanity mirrors open and it would stop buzzing.  I fiddled around with every switch I could find and when I clicked the switch for the (inoperative) rear cargo lamps, the 'gate ajar' light would turn off and I wouldn't need to leave the vanity mirror open to stop the buzzing - small victory there!  I've left it parked for several days at a time and the battery doesn't drain from what I can tell.  I have the FSM volumes for my car, and when weather improves, I'm going to have a friend of mine who has WAY more electrical knowledge than yours truly, try to help me pinpoint the fault or short.  I'll be going through this thread to troubleshoot when I can make it to my friend's garage.

Good luck!  My plan is to return to the quest at some future date and get my cargo lamps to operate without involving the gate ajar switch or turning on the gate ajar dash lamp again.  I think the switches on the cargo lamps just toggle between two ground wires, one of which is fed through the gate ajar switch, but I'll remove one of the switches to confirm this and that it is operating properly.  It should be possible to reconnect the hot wire to the cargo lamp switch and then make sure there is only one operable ground leaving the switch.

Just to be sure, I'm sacrificing a chicken before I get started.  Those wires are evil.

At least you have it narrowed down to the wiring in the gate.

The cargo bay lights have the switch on a ground side that is parallel to the gate open switch. If you can get power to the orange wire (put a wire between the two parts of the connector) the lights will light up with the switches in the on position.

Hooray! I spliced a wire into the orange (hot) wires on each side of connector C405 as suggested by Fred. Now I have working and switchable cargo lights, and the gate ajar indicator light is still not on.

The only problem now is that I lost the black button from one of the cargo light switches. Anyone have a spare they'd like to sell?

I have a few. I can send you one if you pay the postage. Probably $1. Check my parts for sale thread in the vendor section for my paypal/email.