bronto

Trying to get some remaining gremlins eliminated on my '79.

The interior lights are functional but they don't come on when the doors open.

It's been a while since I've messed with them, my recollection is that on the switches, rocked all the way one direction is "always on" (this works now), in the middle is "always off", and rocked the other direction is "on when open".

I think I recall the front light goes on when the doors are open, and the rear one goes on when the hatch is open(?).

I have checked all the fuses and they're good. I also looked a the fuse/relay chart to try and determine if there was a relay that controls the "door open" behavior, but nothing is labeled that way.

Thanks.

Manfred

What about the door switches themselves? They can fail. Try opening the doors and working the door switches with you finger to see if you can get the lights to come on. I think the switches themselves can either stick or fail, or perhaps the wires can crack in the door brace where they cycle every time the door open and closes.
Dan

bronto

I suppose that's possible, but it seemed unlikely that they'd both fail at the same time.

I suppose I should review the back story, my car was parked from October to March while it was being painted. Both doors would trigger the lights before it was parked. But there is something weird going on with several blown fuses when I got it back, so something goofy might be going on somewhere.

bronto

It's been a busy year, and I am finally back to working on this issue. Nothing's changed, any further suggestions would be welcome.

All the lights are functional, but NONE of them come up when doors or hatch is opened. It's not a matter of switch position. Is there a relay that controls these that isn't involved with manual operation of the lights?

Leon Speed

On my 89, yes. If I open the door and press the pin switch, if it is really quiet I hear a relay clicking. Maybe your MY has a relay for the interior lights as well. Another possibility is that the wiring on the lighting fixtures is reversed. There are two positive wires and one ground. Change the positive wires around to check. Be careful as the plastic can be brittle.

bronto

Not obvious to me:

http://928intl.com/repair/Relay/earlyrelay.htm

bronto

Jim's got an excellent resource page on the OB's:

http://928classics.com/4/post/2014/0...ual-78-79.html

And this is by far the best scan of the wiring diagrams I've found, yet I still can't make them out. The wires leading from the door switch appear to be labeled F5, yet I can't see where they go. Same is true for the "roof light", they lead into a harness of unknown destination. I thought I knew how to read wiring diagrams, but I guess not.

Alan

On a '79 no relay - they are driven directly by the pin switches.

Test the door & Hatch switch operation at CE plug U2 or Z5 or F5 (all connectors & switches in parallel), here: ground = door/hatch open, 12+v = door/hatch closed).

Those are not the most helpful diagrams for you to use - use the ones from the Factory Workshop Manuals - you will find them much easier to understand see page 97-39

It could be as simple as having them wired incorrectly many many people who take them out never bother to check what is connected where... and accept its connected right if the lights work in at least one mode - were these taken out for any of the work done?

For the roof light: brown to frame, brown/white to switch & red to bulb end - In the door lights brown & brown/white are interchangeable (but match the switch operation direction side to side).

In the hatch sometimes there are alternate colors: brown to frame, white to switch & green to bulb end. Use whichever applies to what you have installed.

Alan

bronto

Thanks Alan, don't have a copy of the WSM handy and am very low bandwidth internet for the weekend. I'll try what I can....

bronto

And no, not disconnected for other work as far as I know.

Is this one continuous circuit? If there is a shorted wire near one switch, would it affect the others?

bronto

You say there should be power at F5 with the door closed? Opposite of what I would have guessed.

James Bailey

did they paint the door jambs ??? did they unsrew the door pin switchs...rear hatch check the ground wire behind the tool kit cover on the bottom of the hatch lock post receiver. Brown with white stripe hooks to chassis.

Alan

Yes that is correct, if anything on the switched ground wiring side (Brown/White) is shorted to ground then the lights will always be on in both switched modes.

Only an open circuit causes the lights to stay off. People talk of power side shorts a lot - its actually very rare - because power short usually cause blown fuses and are obvious.... On interior lights a short can cause "on" behaviours when you'd expect the circuit to be off - but thats usually obvious too.

If the brown/white wire of any of the roof lights is connected by mistake to the fixture frame connector then all the lights will lose the switched mode and will be permanantly on in both non-off positions. In this case the door end lights will likely always be on leading to major battery drain issues.


If the red wire is connected to the switch and the brown wire to the bulb (folks who have no clue what the connections are supposed to be seem to favor adopting this configuration - probably due to a missunderstanding about how interior lights usually work). In this case the lights will work in permanent mode when switched one way but do nothing when switched the other way.

Alan

bronto

Bingo! That was it. The wires were all crossed up. Can't explain that. They worked when I left it to be painted, they didn't when I got it back. Hmmmm.....

Thanks, guys.