Wiring connects on the firewall?

Tiny
DAVIDBURNETTE
  • MEMBER
  • 1999 FORD F-250
  • 7.3L
  • V8
  • TURBO
  • 4WD
  • AUTOMATIC
  • 350,000 MILES
Looking for a pin diagram explaining what the wires are for on a 99 F250 7.3 diesel. Plug in question is the bottom large grey plug on the drivers side. Plug connects on the firewall and goes out to engine bay.
Saturday, March 21st, 2026 AT 7:02 PM

3 Replies

Tiny
AL514
  • MECHANIC
  • 5,575 POSTS
Hello, can you count how many wires there are in that connector? There are quite a few bulk multiple junction connectors like that on this truck, I believe I have the correct one here, looks to be about 42 pins. Ill post a couple diagrams of bulk connectors and you let me know which one it is by wire coloring.
Was this
answer
helpful?
Yes
No
Sunday, March 22nd, 2026 AT 11:38 AM
Tiny
AL514
  • MECHANIC
  • 5,575 POSTS
These are a couple bulk connectors, on most lists for harness connectors will give some idea of their location by their number, so C138 and C103 for example, could be towards the front of the vehicle and the higher numbers will be the connectors going further back towards the rear. I will keep looking through the list of connectors in service info as well.
Images (Click to make bigger)
Thumb
Thumb
Was this
answer
helpful?
Yes
No
Sunday, March 22nd, 2026 AT 11:48 AM
Tiny
AL514
  • MECHANIC
  • 5,575 POSTS
Service info this old doesnt always show the locations of components or connectors in all cases. But this should help, it looks like from the dash view here, C1049, C1050, or C1051 could be one of the connectors youre trying to ID being in that location, Im pulling up those connectors right now for you.
Image (Click to make bigger)
Thumb
Was this
answer
helpful?
Yes
No
Sunday, March 22nd, 2026 AT 12:22 PM

Please login or register to post a reply.

Related Engine Wiring Content

VIEW MORE