Community Forums

Sanchez_315er · 08-10-2021, 01:43 PM

I had a wonderful failure of my AP system. It's on a 2003 that only had 10K miles on it. When I bought it and drove it for the first few months of ownership, all was good.

When taking it out for a spin and fill up in the spring, it started with not immediately energizing the AP system when shifting out of park. That rapidly became more of a problem. It also suddenly engaged while driving down the road at 40MPH. GREAT! I was able to get it to the driveway where it refused to energize the AP system.

I started by replacing the Rotten Brown and Rotten Gray. Nope. I tested the TWO relays, and they seemed to be good. I ordered a PARK/NEUTRAL sensor for my 4L80E and both relays.

Well, the relays were at NAPA:
70A: ECH AR282
PARK/NEUTRAL: ECH AR172

I put those in and BAM, it was working!!!!!

Now that second relay was a prick to find. Mine was found by opening the doghouse and looking at the top of the tunnel on the driver's side over the engine. It was dangling there upside down (perfect for collecting moisture).

IMHO, replace the rotten ones and the relays and see where you are. I feel that the P/N transmission switch is unnecessary, but for $35, I'm keeping it in the RV as a just in case.

I hope this helps others. Do not miss that smaller relay in your troubleshooting/replacing. I feel that it is a weak link due to its placement.

donr103 · 08-10-2021, 01:52 PM

Great info.. we are always interested here on a/p post.. and yes.. always change relay and switches on a/p every 2 to 5 yrs.. carry spares and change out the oil.. the moisture collects and clogs up Vickers valve.. so keep those post coming.. and big thank you for posting part # s as always good luck and let us know what you did and maybe better members then me will help you

Isaac-1 · 08-10-2021, 08:00 PM

Thanks for reminding me mine is due for a new relay

Sanchez_315er · 10-24-2021, 08:56 PM

Took a trip with rain in parts of it. While driving along, I heard the pump come on. Brake did not engage. Pulled over immediately and unplugged the pump. By process of elimination, figured out that the big relay was stuck on. Luckily had a spare and was good to go. Pulled the relay apart and found moisture. In my haste, I didn't mount it to the frame and left it dangling. Might not have got moisture if I didn't. Lesson learned!

donr103 · 10-24-2021, 09:10 PM

When ever you get the chance.. use electric contact cleaner to clean relay harnesses and wire brush.. then put dielectric grease on both relay and harnesses.. just for extra protection... good luck and keep the a/p posts coming.. we now have a new generation... like me.. that are learning..