head lights / wireing ( 91 w250 )

[whitevamp]

first id like to say hello, to everyone, first time posting on here.

this is for a 91 w250 Cummins.

ok now to the issue.
to start off i had a overcharging problem, ( so bad it tottley fried the battery, and voltage reg ) got that fixed, then had a pulsating volt gauge, got that one fixed, and in the process found out that about 3 feet of the under dash wiring was melted so i got a new under-dash wiring harness, thought i had every thing fixed, ( wrong! ) had some other shorts. got that done now i have a 12volt positive ground. so i found some wires melted in the engen bay ok replaced that still same 12volt positive ground. ( ohh and i should mention that i only get that wile the headlights are on. So its in the head lighting cercit. ( not the park light ) so i go through the both new wiring harness and i find out that the new under-dash wiring harness is starting to get burnt in the head light switch socket connector.
so my question is.
1. what have i missed?
2. once fixed where would i find the instructions on adding in the relays for the head lights?
3. should i rip out the under-dash harness and check it out.
4. scrap truck? ( ohh darn cant do that its a friends. )

ohh yea i have also unpluged the harness connector that runs to the rear lights. ( the blue connector under the dash by the string column. to isolate the front / back )


and thanks in advance for any help on this.

EDIT:
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also i had forgot that while the headlight bulbs are pluged in i have the positive ground, but if i unplug them then no short. ( have replaced bulbs no change. )
and if i unplug the turn signal housing switch. ( turn, flasher, hi/lo, wiper's ) short goes away, have replaced it. no help.

[huntinguy]

Here are some wireing diograms.http://dens-site.net/Dodge_CTD/1991.5-Wiring_Diagrams/

[whitevamp]

thanks for the diagrams.

and i have resolved the issue.
some one had taken a hot wire and ground it on the headlight cercut. also there was no ground wire for the frame, i added it and all is well now.
( there was 2 grounds one to the motor, and one to the chaise. but none to the frame. )

[dpuckett]

The headlight switches were a weak link in our trucks, esp the duallies with all the govt mandated extra lights. I've added relays to my tail light circuits in all my duallies, and will do so on this SRW truck just because I can. I've also put the high beams on relays on a few trucks, with nothing but positive results.

Dan