Series III dash wiring help needed

[Xplitive]

Troubleshooting electrical over the internet is a bit of a gamble but the fine folks here have entertained me, and learned an enough to have everything working.
- short response is - check for power at the socket, believe at least one of the 2 panel light sockets grounds through the instrument case, if not the case then through a daisy chain of ground wires at the back of the cluster. If no go there, start backing up to check for power source and grounding. I have my dash open for a short while longer if you need any pics.
longer response:
- S3 wiring diagram on hand? There is a high resolution one, in color, on one of the wiper threads.
- what are you starting with? Fun fact, replacement looms can have a lot of extra wiring options in them. Complete rewire or chasing various inop circuits on an OG install?
- probe light?
- meter to check continuity?
-if the vehicle has been sitting a while, found many of the switches/relays needed to cycled, jiggled, cleaned connection, etc several times to start working again. This was definitely the case for my panel light switch.
- fuse box decoding: Brown wires - constant hot circuits, white wires - switched power into green.

[Monty]

No apologies needed. This truck is a 1975 Series III LHD 88. There's just a couple things left that are still a mystery to me. I have replaced the main and rear looms. Made a sub harness for the reverse lights, and replaced or refurbished all the lights. What's left...

-figure how the dash indicator lights ground. Presently they have a black w/red trace joined with a insulated female spade. Don't see where it plugs in


-figure out the panel light switch. There is the simple 2 position 2 pole but it's in what I think is a warning light hole. There's a fancier switch next to the headlamp switch. It's a 3 position with 6 poles. The label would indicate up off, middle panel lights and down dome light.


-last there's a black socket with a white with red trace and a black wire. It came bound to the panel light wires.

@scott
Sorry to revive and old thread, but did you ever figure out how to wire the instrument panel indicator lights? I’m stuck in the same spot. Also, that light socket goes into the rear center of the fuel/water temp gauge cluster, but I’ve not been able to get mine to work

[64osby]

Put a star washer between the spade and the bulkhead to help with the ground contact.

[loose gravel]

That should work. Just remember to check yer ground when the wipers malfunction! ;^)

[scott]

i don't want to alter the new harness. i'm just going to screw a couple of these to the bulkhead and carry on

[loose gravel]

Scott, why not just make a "common" ground for them both? Put a ring on one end with 2 of whatever spades you need wired to it.

[series guy]

You can buy ring terminals with a male spade on them if you don't want to modify your harness.

[scott]

On our '75 SIII hardtop the wiper motor grounded to a ring terminal (already on the end of the black wire) that mounted to one of the wiper motor clamp bolts. I think the drawing shows something similar except with a spade.

Bob

it's the damn spades that are driving me nuts. the old loom and the new one both have insulated spades at the end of the ground wires and this screams at me to find where they plug in

[siiirhd88]

On our '75 SIII hardtop the wiper motor grounded to a ring terminal (already on the end of the black wire) that mounted to one of the wiper motor clamp bolts. I think the drawing shows something similar except with a spade.

Bob

[scott]

Fixed it for ya! It's been too long to remember where the wipers ground on a S3. I put the single wiper in my 109 and just grounded it in the motor area with a sheet metal screw. As you are probably aware black is the ground so if you find an MT spade within reach it's a go! The more you connect up the more other connections seem obvious.

so you're saying just get some "ring terminals" and sheet metal screw them to the bulkhead? that's about where my freak'n fed up head is about to go with this crap. i only have these two female spades left. the dash turn arrow lights share one and the plug that goes to the wiper motor has the other.

[loose gravel]

look at the ground wire...why does this diagram specify "soft top only" for what looks like a ring terminal that is probably screwed to the bulkhead for the ground's connection? where does the ground spade plug into on a SWB (hard top)?

Fixed it for ya! It's been too long to remember where the wipers ground on a S3. I put the single wiper in my 109 and just grounded it in the motor area with a sheet metal screw. As you are probably aware black is the ground so if you find an MT spade within reach it's a go! The more you connect up the more other connections seem obvious.

[scott]

look at the ground wire...why does this diagram specify "soft top only" for what looks like a male spade connector that is probably screwed to the bulkhead for the ground's female spade connector? where does the ground spade plug into on a SWB (hard top)?

[siiirhd88]

White with red trace is usually the 'start' wire from the ignition switch to the starter solenoid. I haven't a clue why your wire loom has a light socket.

Bob

[scott]

kind of stoled this from landyzone. best diagram i've found thus far. it answers my second question regarding the instrument panal switch. the simple two position two pole is for non swb whereas the three position 6 pole one is for the swb's as they have dome lights. still not sure what's supposed to be in that hole the simple switch is in. the one in the picture that my left index finger is pointing at.

[scott]

The hazard on the main dash panel is an early feature by 1973 the hazard was moved to the center accessory panel. The clip is located slightly to the left of the steering column below the two large washers. Sorry for the poor photo.

No apologies needed. This truck is a 1975 Series III LHD 88. There's just a couple things left that are still a mystery to me. I have replaced the main and rear looms. Made a sub harness for the reverse lights, and replaced or refurbished all the lights. What's left...

-figure how the dash indicator lights ground. Presently they have a black w/red trace joined with a insulated female spade. Don't see where it plugs in


-figure out the panel light switch. There is the simple 2 position 2 pole but it's in what I think is a warning light hole. There's a fancier switch next to the headlamp switch. It's a 3 position with 6 poles. The label would indicate up off, middle panel lights and down dome light.


-last there's a black socket with a white with red trace and a black wire. It came bound to the panel light wires.