Bounder: PCM Ground Mod

[chuckbear]

There is a service bulletin for 1999 to 2000 F53 issues with problem transmissions shifting and speed sensors reading speed when stopped. The repair bulletin requires a replacement harness that is no longer available to improve the ground for the OBD wiring harness. Can anyone provide me with a step by step to do the modification without the replacement harness? Thanks. Chuck

[Waiter21]

I did the TSB on my Southwind last spring, without the harness.. soldered a new wire on the existing ground pins.. I did a writeup with photos on my blog site..

F53 Transmission shifting weird in 1st and 2nd gear – 1999 Southwind 35S

..

[chuckbear]

Perfect. That is exactly what I needed. Chuck

[mrwrench]

Originally Posted by Waiter21

I did the TSB on my Southwind last spring, without the harness.. soldered a new wire on the existing ground pins.. I did a writeup with photos on my blog site..

F53 Transmission shifting weird in 1st and 2nd gear – 1999 Southwind 35S

..

what is the green ground for?

[Waiter21]

I assume you're talking about the green wire in my photos.

Refer to the article..

F53 Transmission shifting weird in 1st and 2nd gear – 1999 Southwind 35S

I didn't have the OEM retrofit wiring harness, so I elected to leave the original 7 pins installed in the plug and splice the wires that come from those seven pins to t\a new wire, my green wire.

I then drilled a new hole as called out in the TSB and installed my green wire under that hole.

[mrwrench]

where is the original ground?
in that green bolt?

[Waiter21]

where is the original ground?
in that green bolt?

I don't know where the original ground is for the original 7 wires. I'm guessing somewhere on the tranny/engine or frame..

The green bolt originally had two original ground lugs under it. I'm not sure where they come from. The TSB has you move these two ground lugs to the new hole, and use the old original hole for the new 7 pin wire ground.

Are you able to download and read the TSB?? It has you drill a new hole near an original ground, then put the new 7 wire ground on that hole..

I don't know why Ford drilled a new hole and didn't just install the new 7 wire under the old hole. I elected to follow the TSB to the letter and drill a new hole. Make sure the hole is clean of any paint. It should be bare metal.