Parasitic Draw SOLVED 2010 EL

[Martno]

I posted several months ago concerning a long term parasitic draw problem. Did A LOT of work on it and even paid over a 1k for a shop to not really find anything.
I finally FOUND my issue… it is the 12 volt charging supply to the trailer light harness.
I found the problem, now to resolve with a fix.
Will start with a new relay… only variable I can think of.
If you have any insight, please reply. This post is to help someone else in their search.

 

[BigOleFordFan]

Good to know, thanks for the info

 

[99WhiteC5Coupe]

I posted several months ago concerning a long term parasitic draw problem. Did A LOT of work on it and even paid over a 1k for a shop to not really find anything.
I finally FOUND my issue… it is the 12 volt charging supply to the trailer light harness.
I found the problem, now to resolve with a fix.
Will start with a new relay… only variable I can think of.
If you have any insight, please reply. This post is to help someone else in their search.

Factory harness, or aftermarket?

 

[Martno]

Factory harness, or aftermarket?

Factory harness.

 

[gray_ghost]

I used to have a 2010 Expedition with the HD tow package. I was plagued by a parasitic draw that I never solved. I am a retired engineer and ex-auto mechanic with considerable troubleshooting skills. I used several methods to isolate the draw with no success. I finally sold the 2010 and bought a 2019 Expy Platinum...problem solved. Please give us more information on how you determined that the trailer battery charge circuit was responsible for your parasitic draw.