So by now we all know about the Inertia Switch that is on the firewall and is supposed to cut fuel in the result of a big crash. Well, this weekend while wheeling out in Oceano Dunes SVRA near Pismo Beach with NCLR/SCLR I seemed to come across another.

Twice this weekend after hitting a dune pretty fast and coming down hard my hazards were flashing. First time i didnt notice it until someone was like hey your hazards are on. I thought that was weird, so i checked my blinkers and my hazard switch and all was ok. Hrmm.. So i turned the truck off and back on and the hazards went off. Didnt think much of it until the next day when same thing happened, came over the crest of a dune pretty quick and landed hard and hazards were flashing yet again. This time i knew what it was and cycled the truck off and on and it went away.

I didnt have to reset the switch under the hood at all fwiw and the trucks fuel supply never cut off.. Just thought it was odd.

My truck:


Colin from NCLR catching some air:

 

FWIW, i searched the D1 RAVE for inertia and came across this bit after seeing the fuel pump inertia switch mentioned 50 times..

Figured it was something along these lines..

 

Yep, one keeps the fuel from feeding a fire during a wreck, the other one unlocks doors so people can drag you and your kids out of the wreck.

 

WTF...I replaced the wrong one!!!

So how the heck do you fix that one?

 

It is your hood, it is popping open on the hard landing.
Open your hood, there is a button, it is part of the alarm and will set off the hazards if the hood is messed with.
Happens all the time, unplug it, or adjust it, your choice.

 

Happened to me in Moab when I hit a creek bed too hard. Buddy with me in a jeep quipped " maybe you should ring up the queen!" after I could not figure out how to shut them off.

 

I'm not buying into that one. If the alarm were armed then maybe, but then you wouldnt be driving with the alarm armed because it kills the fuel pump.

With the car running the hood pin for the alarm wont do diddly. I could drive around with no hood all day and that alarm plunger for the hood could care less. Now once i arm the alarm then that's a whole other kettle of fish.

There is a secondary inertia switch in the alarm system ECU. That is what is getting tripped with rough landings in my case and what has seemed to go wonky in wheelgarage's case.

Check and make sure the alarm ECU is solidly mounted to the chassis. If its banging around near where it lives then that could be giving you false inertia readings. Other than that your other option is to replace the alarm ECU.

 

The alarm ECU is a green box that is mounted on a thin metal plate beneath the cruise contol ECU, ABS ECU and Window Lift ECU with a few 7mm bolts. It's not mounted anywhere near the chassis.

 

Not the hood.

I can confirm that it is the alarm ECU as well. Green box mounted under the glovebox above passenger footwell. At some point before I got it the mounting tabs were broken off of mine and it was taped up in there. I had to take it down to get to the relays when I reset the codes for my ABS using the paperclip method. Well, I left it dangling down for a few days in the passenger footwell before I re-mounted it, and every time my wife/kids touched it with their feet the hazards would come on and I would have to cycle the key to get them to turn off.

 

haha thats awesome