I was able to figure the constant wait-to-start indicator on and will try to explain in case anyone else has similar problem:

First, contrary to what advice and photos in earlier posts on this thread state/show, on the '83 the glow plug wait-to-start wiring is not fed power from the glow plug relay. There is a relay in the dash directly behind the indicator lights panel (has 3 idiot lights-- wait-to-start, engine temp warning and water-in-fuel). This relay is a normally closed type which needs a signal from the engine mounted controller to "open" (thus cutting off power to the indicator light). So when the controller fails or is unplugged and a manual glow plug control switch is installed to manually activate the glow plug relay, this relay never gets the signal to "open" and thus stays on constantly.

So to solve the problem, the dash overlay needs to be removed to access this relay and the relay removed. This removes the ground for the indicator light and thus the light never comes on-- problem solved??

I do have photos and scans of the wiring diagram but will need some pointers on how to upload these to this discussion?? If someone can walk me through how this is done, I will be glad to include these in another post.

Not sure why but looks like I don't have access to uploading images or adding attachments. Maybe because this is one of my first posts?? anyway until this gets resolved I won't be able to post the schematics and photos

 

You have to get 25 posts to upload photos. I don't know if you can just link it if you put it in a place like Photo bucket or your gallery. To link, simply copy and paste, or do the hidden link trick, which is name of link This reduces the link to the title you giveit, instead of the long stream of symbols. Otherwise, upload to your gallery, then under the pic is the link for forum codes, and you can get the link code there. You have to view your gallery like you were a guest viewing it, not through edit.

That is a strange way to do it. What you can do if you want the light to work is to use a signal from the GP relay to trigger the light by bypassing the relay and hook like we were saying to the relay, then run a wire to the output side of the relay terminals. This would trip the light when power is applied directly, rather than through the relay.

 

Thanks for explaining why I wasn't able to "embed" photos/scans in the post-- will research how to upload to a gallery when I get time and maybe post the photos/scans then??

I suppose that revising the connection for the wait indicator latching relay as fellro86 suggested might work but not sure as this isn't a simple relay that I am familiar with-- in the wiring schematic and discussion, this relay is called a "latching relay" and has the normal switching leads (which in a regular relay has one +12V and one ground connection) both connected to +12V power sources. Regardless I am not too hot on that idea because the light really isn't working correctly and I can just see someone unfamiliar with the system hitting the manual switch and wait for the idiot light to go off (which I suppose it would maybe as soon as she/he hit the manual switch). Anyway with the manual system the light is meaningless so I am happier with it not coming on at all which is easier to do by just pulling the latching relay. Would need to get to the relay to make the connection that fellro86 suggested anyway.

Thanks again for the help. Hope to be able to get the photos/ description scans posted soon.

 

On checking my wiring diagram again, it does say 1984 thru 1986 near the Diesel Warning Module picture.

No diesel option in the 80 to 83 diagram.

Sorry for the confusion.

 

My wiring, like most, kicks the light on only when the switch is activated. It is kind of an alert for two things: one is to let you know the system is on and two to let you know when something is wrong. It goes off because the GPC tells it to, if you bypass this controller it wont go off on its own. Know what i mean. If i were you, i would re-do my system so that it makes sense. Welcome to my world of having an F150 body dropped onto a F350 chassis and drive train. The wiring is a friggin nightmare!!!

 

Dave Sprongle-- Okay, what I am concluding is that my '83's wiring must be different from the '84-'86 which is I suppose not too much of a surprise as it was the 1st year the 6.9 was offered in the F250. Again for benefit of possible other '83-ers I will attempt later to attach some photos of the relays and wiring schematics when I have ability to attach photos & scans to posts.

Thanks to all for the advise andhelp. For now the issue is resolved for me