Notices
1999 - 2016 Super Duty 1999 to 2016 Ford F250, F350, F450 and F550 Super Duty with diesel V8 and gas V8 and V10 engines
Sponsored by:
Sponsored by: Real Truck

Electrical Gremlins

Thread Tools
 
Search this Thread
 
Old Sep 26, 2018 | 01:19 PM
  #1  
JOE-Lambert's Avatar
JOE-Lambert
Thread Starter
|
New User
Joined: Sep 2018
Posts: 1
Likes: 0
Electrical Gremlins

Hi everyone, new member with a doozy of a problem. Any advice would be welcome.

Background:
1999 F250 Superduty, 7.3L Diesel, No mods other than a remote start/lock installed before my ownership, 178,000 miles, no known engine issues.

18 months ago I got into the truck during a rain storm and found the glove box was full of water and the cabin functions (fan, lights, radio) were acting erratically. The speedometer was also acting very strange. I had a glass company come out and replace the windscreen gasket and they reported that the body had some rust under the gasket that may interfere with the seal working well. I tracked the speedometer issue down to a bad speed pickup on the rear diff. After a week or so of drying out the cabin functions all sorted themselves out, mostly. Every now and again when I turn off the truck the cabin fan will keep running or the radio may not turn off when I shut it down. I've been living with that by just turning them off when it happens which isn't very often.

Now things start getting interesting. 3 months ago the locks started to misbehave, if you lock the doors the key won't open them from the outside, it's like the electronic locks are pulling the locks down very gently. On the other hand, when you get into the truck and close the door, it won't latch at all unless the lock is engaged. You can probably imagine that this is a bit frustrating and has led to a few trips through the rear window.

Today the horn went off and stayed on until I put the key in the ignition. This happened three times before I yanked the fuse.

Clearly something is wrong, I'm guessing water has gotten into the cabin controller? Can anyone give me any guidance if I'm missing something or what parts I need to start replacing? The truck still pulls great and doesn't have that many miles for a diesel but it's getting a little ridiculous.

Many many thanks,
Joe
 
Reply
Old Sep 26, 2018 | 04:14 PM
  #2  
brian42's Avatar
brian42
Lead Driver
Veteran: Navy
15 Year Member
Community Favorite
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
I recommend checking for indications of moisture and water damage in your Generic Electronic Module (GEM - which is behind your fuse panel in the lower dash under the steering column), the fuse panel, as well as the Powertrain Control Module (PCM) which is above the parking brake pedal. A visual inspection under the dash wouldn't be a bad idea either.

This would give you a good idea where the water may have gone.

I'm not sure if the horn runs through the GEM but the door locks do.
 
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
fred-texas
Electrical Systems/Wiring
1
Jul 4, 2018 08:16 AM
jose0504
1999 - 2016 Super Duty
17
Feb 14, 2018 08:43 PM
Harry Butch Barrett
2004 - 2008 F150
1
Jun 23, 2013 10:25 PM
dlaude6
Electrical Systems/Wiring
7
Jan 4, 2012 10:37 AM
dominant motorsports
1999 - 2016 Super Duty
3
May 8, 2010 12:44 PM




All times are GMT -5. The time now is 08:38 AM.

story-0
Top 10 Fords at 2026 Carlisle Ford Nationals

Slideshow: Top 10 Fords at 2026 Ford Nationals

By Joe Kucinski | 2026-06-09 11:10:08


VIEW MORE
story-1
3 Best / 3 Worst Parts of Modern Ford Ownership

Based on years of owning multiple modern Ford products.

By Brett Foote | 2026-06-09 10:53:36


VIEW MORE
story-2
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches

SPONSORED: From muddy boots to rain-soaked cargo, these upgrades address some of the most common frustrations Ford truck owners face every day.

By Pouria Savadkouei | 2026-06-08 18:50:34


VIEW MORE
story-3
Every 2026 Ford Engine Explained

Here's everything you need to know about every Ford engine available for the 2026 model year.

By Brett Foote | 2026-06-05 12:58:01


VIEW MORE
story-4
10 Ugly Ford Trucks That We Still Kinda Love

Slideshow: 10 ugly Ford trucks that we still kinda love.

By Joe Kucinski | 2026-06-03 09:51:16


VIEW MORE
story-5
10 Things Every Truck Owner NEEDS (2026 Edition)

Slideshow: the best gifts for dads & grads

By Michael S. Palmer | 2026-06-03 15:43:58


VIEW MORE
story-6
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath

Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.

By Verdad Gallardo | 2026-06-03 11:38:36


VIEW MORE
story-7
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer

Slideshow: 10 most expensive Ford trucks ever sold on Bring a Trailer.

By Joe Kucinski | 2026-05-27 16:24:34


VIEW MORE
story-8
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)

Here's everything that has changed for the latest model year.

By Brett Foote | 2026-05-27 16:17:28


VIEW MORE
story-9
Top 10 Ford Truck Tragedies

Slideshow: Top 10 Ford truck tragedies.

By Joe Kucinski | 2026-05-18 19:34:33


VIEW MORE