Red Engine-ABS/ATC Malfunction light after rain

[Challenger]

Ive had a few red engine Macks kick the ABS, ATC and malfunction light on after raining.  Its always cleared and only came back after a good rain.  Ive feel like Ive been looking for this problem for years.  Our new Granite (1500miles) did it, but this time stayed active.  I found water in the chassis connector.  There are 2 connectors just above the air dryer, left frame rail, just behind cab.  The green one has the abs/atc wires in it.  Cleaned out and applied dielectric grease to the connector.  Cleared codes and its never came back.  Did this to all the red engine Macks and I have no more abs/atc and malfunction lights on after rain.   Also did the same to the black connector

 

Figured I cant be the only one with this problem. 

 

Edited December 12, 2019 by Challenger
Left not right

[Mackpro]

We fight this problem every it rains as well. On our CXU daycabs we find the harness shorted to ground on the inside of the driver side frame rail . About half way between the. Back of the cab and the 5 th wheel. It seems Mack only makes one length of wiring harness ( can’t remember if it’s the front or rear ) . So on the shorter wheelbase trucks where the harness is to long , Mack folds it over on top of its self and zip ties it . Over the years the excess harness rubs the frame rail that’s it’s laying on and the issue shows on rainy days . 

[fjh]

This here issue is even more prevalent when your in an area where  salt or brine is used on the roads it sucks the Cheap  wiring  thru out the truck is affected  def tank wiring also effected with in one or two seasons!