show your fix for busted old-style cargo lights

ehall said:

Alright I got the stock lamp/switch/wiring figured out. It has one power wire (pink at harness), and two ground wires.

One of the ground wires (yellow at harness) is on the same ground circuit as the other interior lights, so when you open any of the passenger doors or twist the headlight knob, the cargo light comes on with all of the others.

The other ground wire (violet w/ yellow stripe at harness) is the hatch ground switch in the latch assembly. This wire then goes into the switch in the cargo light (the chicklet button that is frozen), however it also feeds the rest of the cabin light ground. In one position, opening the hatch will close the ground circuit and all of the interior lights will come on, but in the other position the ground circuit is interrupted at the cargo lamp and none of the interior lights come on. [This is all with the '91, so whoever finds this thread in a search later take note.]

If I want to drive work lights in the hatch from the cargo lamp switch, basically all I need to do is run power into the hatch and tap it into the latch ground, then whenever the hatch is open and the cargo lamp is on the lights will come on. However this would also mean all of the other interior lights would be active too (the cargo lamp switch activates them all), and I don't really want to do that.

Another option would be to run power into the hatch, with a separate switch on that power lead, then when the hatch was open I could use the cargo lamp for interior lights and the dedicated switch for work lights. I still do not like that though, since if I have the work lights on I will probably want the cargo light on too, but will not want all of the other interior lights on.

So... what I am going to try is taking the cargo light switch off the interior light circuit, and tying the work lights into the remaining circuit. This way I can turn the work lights and cargo light off and on together, with both of them being fed by the latch switch. I am trying to figure out if I can also keep the cargo light on the other ground circuit, so that I can turn it off and on by rotating the headlight knob or opening a passenger door. I think I will need a diode to make this work.

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i'd like to know how this turns out for you. i've been trying off and on to work out something like this for the rear cargo light for some time now. i get tired of staring at the wiring diagrams and connecting/disconnecting power and grounds. got some odd results, but not what i want yet. one of the results was putting a second cargo light(with button) up front in place of the stock lamp, just to see what would happen. it works normally, except that i can now turn the interior lights on and off with the little button on the front light, instead of having to turn the headlamp switch knob or open a door. i left it like that.

Just last week, the hatch dome light on my 97 fried itself. I went to Radio Shack, bought a new switch that looked pretty close to the stock one, and stuck it in there. While at it, I swapped out all the dome lights to led's to reduce the current going through that switch. The Radio Shack switch looks way better quality, so I doubt it will be a problem though. I think it was $2.49 for the switch and maybe $20 for the led's.

...frakkin' bad ju-ju with this thread. After telling y'all about my switch on the cargo light, something decided to crap out with the whole thing. It's been crazy 'round here for the last couple weeks so I haven't looked, but I'm thinking it's the hatch switch. The cargo light won't come on at all with the switch, but will light when the front doors are open.

Fun, fun...

Jim www.yuccaman.com

Ten High said:

i'd like to know how this turns out for you. i've been trying off and on to work out something like this for the rear cargo light for some time now. i get tired of staring at the wiring diagrams and connecting/disconnecting power and grounds.

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okay here's some more details and two ways to hack it

The purple and yellow wire coming from the hatch is grounded when the latch opens, and the cargo switch interrupts the ground at the cargo light. When the switch is closed the ground signal goes into the cargo bulb and lights it up.

Meanwhile the interior lighting harness also terminates at the bulb. So when the hatch ground is active and the switch is closed, ground goes into the bulb and then continues back to the interior lighting harness through the yellow wire, which causes the interior lights to come on.

If you want the cargo lamp and interior lamps to be entirely independent of each other, just cut the wire that goes from the bulb to the yellow wire on the harness. The cargo light will still work when the hatch is open, but it will not activate the interior lights. Meanwhile, twisting the headlight knob or opening a side door will still cause the interior lights to come but will not turn on the cargo light.

Another option is to put a diode between the cargo lamp and the yellow wire, so that ground only flows one way. On mine, I put it with the anode side on the harness, so that ground from the interior lighting harness feeds in and activates the ground on the cargo lamp, but ground from the hatch will stop flowing just after the cargo light and will not turn on the interior lights. This means that when the hatch is open only the cargo light comes on, but open any other door or twist the headlight knob and everything including the cargo light comes on. This seemed like the best setup since I figured somebody in the back seat might need to see into the cargo area while driving, but I did not want the hatch to turn on the map lights and footwell lights. If I need the cargo light on but do not want the work lights on, I'll only have to open a side door or twist the headlamp knob.

Next step here is to run another ground wire off the cargo lamp switch back into the hatch, and use that to drive work lights. With this setup the lights in the hatch will only come on when the hatch is open (latch ground closed) and the cargo lamp switch is closed (cargo ground closed). I need to run it from the cargo lamp in order to get the independent control, since the latch ground is always hot whenever the hatch is open. Any power lead will work, and there are a couple in the hatch already as well as a bunch more in the kick panel (IE, the trailer battery wire, which is big enough to power halogens in the hatch).

i dont know how i missed this, my cargo light switch went bad a couple weeks ago. I just put a piece of tape to keep it pressed so it won't stay on.

ehall said:

Napa 549SWD which I picked up this evening

It's the same length as the original but a little narrower. It has a lightweight metal backing plate (which is not the gasket shown in the pic), so by cutting some extra sheet metal to make a secondary backing plate I should be able to mount it to the factory studs and have it cover the hole in the headliner alright. Only other possible problems are that it is a little taller (maybe 1/2") and it is two wire instead of three.

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This doesn't work--the metal backing plate is the ground for the bulb, so it's always grounded. Since the door and hatch light circuits use a switched ground, those circuits no longer activate the light as expected (it's always grounded so it's always on, regardless of the state of the ground circuits). It might be possible to carve a replacement backing plate out of plastic or wood, but it would be a lot easier to stick with the factory lamp and just replace the switch.

Well I actually found a working dome light at the junkyard, the sound bars use the same light assembly but with an extra mounting stud. However I had already started working on a replacement so I did not keep it.

What I came up with was using one of these double dome lights for an RV:



That specific model has a slider switch, with switched power (ground is always active): the first position is OFF, the second position puts 12v power to one dome, and the third position puts power to both domes. There are some other models out there with only a basic switch that turns both of them off and on but I thought I could use this one to control my hatch work lights too.

After a bunch of snipping, folding and soldering, what I came up with is for power to be always hot (like the factory dome), with the switch controlling ground. In the first position there is no ground so both lights are OFF, second position puts ground to both lights, and third position puts ground to both lights and ALSO puts ground to a pigtail wire that will go into the hatch for the work lights. Ground is fed from the cargo light pigtail, so there is one ground wire for the hatch latch, and another for the cabin. The cabin ground is on a diode, so if I open a door or twist the headlight knob then all of the lights come on (including the double cargo lights), but if I open the hatch then ONLY the cargo lamp comes on. In either event, pushing the switch to the last position will ALSO activate the hatch work lights. In order to keep them from coming on when the interior ground is activated, I will have to tap back into the hatch latch ground circuit somehow. Here is a diagram of the switch wiring that I came up with:



There are eight pins, shown as dots. The two unused pins are for the OFF position. There is a little bit of wiring that connects that pins together, which is shown in green, which I kept. The black lines show the wires that go to the bulb housings, and connect on the pins shown (one of these pins is always active in both of the last switch positions, so both lights get grounded in both positions). The purple line shows the hatch ground wire, and yellow line shows the cabin ground wire (in my case I also put diodes on the yellow wire with cathode side on the cabin, which allows ground to pass into the light but not back out). Finally the blue line shows the new ground pigtail that will feed the hatch work lights.

Here's a night-time picture of the double dome lit up. It's pretty freakin bright.



I'll take some pics tomorrow of the light and backing plate I made to mount them to the ceiling posts.

I just replaced the seized/melted OEM switch with a rectangular black on/off switch.

Just used a box knife to cut out the housing to accomodate the larger switch and all was good.

I originally replaced it with one of those those "pointy" chrome toggle switches. I didn't like the way it looked and I think I hit my head on it once, so I switched to the better looking black rectangular toggle switch. Doesn't poke you in the head either.

Blaine B. said:

I originally replaced it with one of those those "pointy" chrome toggle switches. I didn't like the way it looked and I think I hit my head on it once, so I switched to the better looking black rectangular toggle switch. Doesn't poke you in the head either.

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That's why I mounted my cheap chrome "pointy" toggle on the side of the switch. I'd have to drive my head into the roof just to hit that switch... :gee:

Jim www.yuccaman.com

i don't have a cargo light, but some of the dash switches might work. like the ones that control the rear defrost/wiper etc. I just took a few out myself to use for some lighting and maybe an eaton when I get them money. keep it factory looking

In order to mount the double dome light I had to fabricate a backing plate. This serves two purposes, one is that the cargo light kinda holds the headliner against the ceiling in the back, and two is that plastic housing would droop and sag at the ends if it wasn't braced up. What I came up with was to use a piece of scrap sheet metal (part of a door actually) with holes for the two cargo light mounting posts, screw holes and tee nuts for studs for the double dome, and a large open area that lets the wiring out and also prevents the bulb housings from shorting to ground against the body.

Here's a pic of the back, showing the tee nuts glued down



Here's the front with the lamp laying over it. The lamp is off-center because it's just resting on it, not screwed down--when it's tight everything is centered.



Here's what it looks like mounted up



It's really bright and works nice. I was afraid it would be too large but it's a really nice size. They make them in two sizes, and this is the smaller one (11.5" x 4" or something like that), and I'm sure the larger one would be too big.

superbrightleds.com has a panel that should fit into the housings as well, and I will probably get some of those later now that I have this figured out

ehall said:

won't work, I am going to double-duty the cargo switch to activate work lights in the hatch

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What kind of work lights do you plan on running in the hatch?Been thinking of doing the same but need some ideas....

beakie said:

problem with mine now is the glass made it heavier, and without the pins that went into the old light and had the pressure washers on them....

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***at the top of the stud pins is a hex, unscrew it. You can use just about and standard screw to replace that silly pressure nut stud thing.

Are you talking about the small black button for the cargo area light that is located in the speakers console?

If so.....In my case the swith was burned and locked. I boughta very similar one in a small elctronic components shop and it works great.

regards

outlander said:

What kind of work lights do you plan on running in the hatch?Been thinking of doing the same but need some ideas....

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I bought two of the 30-bulb ST series (top of http://www.superbrightleds.com/truck_lights.htm), but they haven't arrived yet

Not quite related question, but any reference for the bulbs used in the early (1989) roof lights?

They're not a standard size in Europe and not listed in the manual.

Previous owner couldn't work out how to switch them off (turned the headlamp knob by accident), so he pulled the bulbs and lost them :doh:

LEDs would be even better.

I got the work lights wired in today. The setup I had in mind did not work as expected, but for now the lights work and are controllable.

Essentially the cargo light has a three-position switch. In the OFF position ground is open and the cargo lights and work lights are therefore off.



In the middle position, ground is passed to the cargo lights, but not to the work lights. Normally this position would also pass ground to the forward cabin lights, but I put a diode on the ground wire at the switch to prevent ground from passing forward.



In the third switch position, ground is passed to the cargo lights as well as another wire that goes into the hatch, which in turn activates the work lights.



Separately, since the diode on the cabin ground circuit only blocks voltage in one direction, I can still open a side door or twist the headlight knob and the cabin lights PLUS the cargo lights will get ground from that circuit (this would still work like this if hatch was closed)



Right now the only "flaw" is that activating the cabin lights will also activate the work lights if the cargo switch is left in the third position. I had planned to prevent this with a relay on the hatch ground switch, but that did not work as expected. What I will do instead is put a jamb switch on the hatch to interrupt the work light circuit. I have a low-amperage magnetic switch that will work in conjunction with a relay from when I was messing with the doorless stuff.

...nothing fancy, but a fix no less.

I just used a switch out of an old home stereo receiver. Ghetto? yes.