I'm writing up this post as a guide or informational post for other users to search in the future.

This weekend my truck's electrical system seemed like it was possessed. At one point or another the truck had the following symptoms:

1. Constant horn blast. I was just driving down the street and my horn went off. Could not get it to stop. I hit the horn pad on the steering wheel and nothing happened. Ended up unplugging the horns cabling and then removing the fuse. NOTE: removing the fuse should be good enough, but at the time I wasnt thinking clearly. I just wanted the horn to stop waking up the neighborhood.

2. The powerlocks on my supercrew would constantly lock over and over again. I had trouble locking the doors. It started with the rear passenger door, then moved to the front passenger door

3. My tail lights would stay on after I turned off the car. Probably would have drained my battery had I not noticed it.

This all happened between Friday night and Sunday morning. The only thing out of the ordinary was that San Diego had a fairly strong rain storm pass over this weekend. Logic lead me to assume that somehow something had gotten a leak somewhere and something got wet or fried.

I did a little bit of research Sunday night and found that the probable culprit was a malfunctioning Vehicle Security Module (VSM known before as BCM). Since I had a busy day at work I had no choice but to drop off the truck at my local dealer.

3 hours and $102.00 later, their diagnosis was: 3rd brake light assembly leaked, water dripped all over the VSM, fried or damaged it.

Dealer wanted $510 in labor to replace the brake assembly, test, reprogram VSM, test again

Parts
194.40 for VSM
74.81 for brake assembly (not sure if the whole thing or just the seal)

Grand total with tax = $804.80

I picked up my truck and thanked the service manager. I called up Tasca and got them to overnight the VSM for $112 + freight. Dealer said I needed to have the replacement VSM programmed to my truck (I guess the keys and keyless entry remotes need to recognize the new receiver?)

So the plan is to buy the VSM from Tasca, take it to the dealer and have it programmed, then do all the labor myself.

Questions I have:

1. Does the dealer need the VSM module installed prior to programing it or can they "bench" program it? (called and asked, but haven't received as call back). UPDATE: Dealer called back, said the VSM needs to be installed and that it it reprogrammed through the service port upfront under the steering wheel.

2. Does the 3rd brake assembly use O-rings? I'll probably eventually replace the entire thing, but presently I don't have the cash and if a quick fix is possible that would be great.

Looks like my total DIY fix will be:

$102 (dealer diagnostic fee, i guess this part wasnt so DIY)
$112+ freight (Tasca VSM)
$102 (dealer programing fee)
$5 (Silicone sealant for 3rd brake light assembly)

Total of $321 + freight. Still stings, but not as much as $804

I'll update tomorrow or Wednesday with my results.

 

Had some extra time after work so I decided to take the old VSM out. When i got to it and pulled it off the wall I could hear water swishing around.

I took off the protective cover and this it what I saw along with some more water...



Other side you can see some pretty heavy oxidation. Nothing looks "blown" but a lot of the traces look "rusted."



All the water I drained out...

 

I received the replacement VSM (it was labeled Body Security Module) and installed it. Right away my remotes stopped working. I drove to the local dealer and they charged me an hour of labor to reprogram it and get everything working again.

 

That sucks.

I've read of others having leaks and problems. Sounds like maybe good idea to seal up the third brake light with silicone.

 

I ended up using some weather striping. Ran two layers around the light (inner and outter) in case one leaked and spaced out the tiny gaps away from each other. We've had a few rain storms come by in the last couple of weeks, and everything has been good.