Failsafe Warning Controller

[brock]

I know this is a stupid question but I can't seem to locate the controller in the truck or in the TM's.

Where is it?

 

[73m819]

on the left side of the engine side on the firewall

 

[MtnSnow]

The warning module is just above the drivers side floor air vent and closer to the firewall. What 73m819 is listing on the engine side is the PCB (protection control box).

 

[Artisan]

The Failsafe Warning Control Module (FWCM) is on the left, above the air vent,
to the left of your left knee. The hazard light box is on the firewall in front of your shins.
If you suspect you need a new FWCM go to www.idahomotorpool.com
and grab one from Alex. They look a little bit different but they work.
Buying a used one is a huge waste of time. I had 3 used units I pulled
off junk trucks and all 3 PLUS my OE FWCM acted different! Just bite
the bullet and buy anew.

I would suggest you replace the LOW AIR WARNING SWITCHES and its ground,
what was it, the #55? wire? It is only 8" long or so under there.
Pull all grounds, grind to bare metal ALL SURFACES and reassemble w/ combination
internal/external star washers and dielectric grease and CLEAN nuts and bolts. I would also
recommend adding a ground from the rear bed to frame and add
another ground from the cab to frame. I did all this and all my lights
etc are nice and bright and shiny and everything works great.

There are a ton of OE grounds;
( I am trying to remember here, I may be slightly off here but

Hood to Frame
Alt to Frame
Cab to frame in engine compartment
Frame to Compressor
Frame to block
Starter to block
Low Air Switches to Frame
Fuel tank to frame

Then I added cab to frame rear ground #4 wire
and bed to frame at the fuel tank ground #4 wire too,
all soldered copper lug ends. All this work was time consuming
but it needed it bad!

Brock these trucks have a BAD HISTORY of the main battery cables
rubbing on the left rear corner area of the engine too. I disconnected
my battery cables at the starter and then ran my hand back there
and I had a HUGE wear spot on my ground cable I think it was. It is
difficult if impossible to see back there. Don't overlook it my friend.
I fixed mine by running a thick piece of rubber hose OVER my cables.
Plans are to move the batteries some day or I would have pulled it all
and reworked it.

 

[brock]

Thanks for the feedback. I knew it had to be somewhere up there.

I am chasing a constantly buzzing low air warning indicator. I have checked all other components but the Failsafe warning Control Module and accompanying wires. I will do so this weekend and report my results.

Thank you @Artisan for the good preventative maintenance advice. I knew about the battery cables when I bought the truck and have inspected them thoroughly to find them in good shape but will keep an eye for future wear.

Thank you again for all the great information and advice.

 

[Scar59]

Thanks for the feedback. I knew it had to be somewhere up there.

I am chasing a constantly buzzing low air warning indicator. I have checked all other components but the Failsafe warning Control Module and accompanying wires. I will do so this weekend and report my results.

A constant low air pressure warning is normally a failed air pressure switch. Have you isolated (unplugged) the pressure switches?

 

[brock]

I have not. Are those located on the tanks?

 

[Scar59]

B,
Yes located at the tanks , two plugged wires to each of them. The system seeks a ground to turn on the horn. With no air pressure, horn sounds. Pull the leads on both, horn should go out. With full air pressure horn should be out (normal) if the horn is still on, disconnect one swithch at a time. Trace the switch wires also, a chaffed wire will sound the horn also. You'll find it.

 

[Alexsha]

Thread hijacking a little here, but my FWCM is on the fritz. Buzzer works when brake is applied or air is low. But it's only sending about 5V to the warning lights. I'm guessing something is fried in the box and I'm searching for a replacement. Am I barking up the right tree?

 

[Artisan]

The low air warning switches are cheap and easy to replace.
I just simply replaced mine anew not knowing how old they were.
It is a safety device, just get new IMO.
FWIW

Alex read my post above about www.idahomotorpool.com

 

[Alexsha]

My switches are working okay. They send the correct signals to the module and the module buzzes correctly. It's just not sending enough juice up to the warning lights. I've found a few suppliers of the module. Just wanting a 2nd opinion of my diagnosis that the box itself has crapped out.

 

[Scar59]

Alex,
Sound like you're on the right track, I would replace the controll module next.

 

[Alexsha]

I think after I fix this I'm going to take some time and build my own module. It'll have 2 switches on it that enable/disable the buzzer for air and brake. Also will include some kind of circuit protector to keep it from frying.

 

[skuhler]

On a related note, (maybe a new thread needed?), when I turned on my M923 this weekend, the failsafe buzzer and lights worked for a minute, then I heard a pop under the dash and all went quiet. Checked the fuse, it was blown, replaced it one time and it blew again. I'm guessing a short in the module. My question is; any harm in running it with the module out? ABS still work?

 

[simp5782]

On a related note, (maybe a new thread needed?), when I turned on my M923 this weekend, the failsafe buzzer and lights worked for a minute, then I heard a pop under the dash and all went quiet. Checked the fuse, it was blown, replaced it one time and it blew again. I'm guessing a short in the module. My question is; any harm in running it with the module out? ABS still work?

No. As long as you pay attention to your gauges. Abs will work. I have mine unplugged for personal reasons.

Sent from my SM-G935P using Tapatalk

 

[skuhler]

No. As long as you pay attention to your gauges. Abs will work. I have mine unplugged for personal reasons.

Sent from my SM-G935P using Tapatalk

Thanks for your quick answer. That's why I like this site, quick and not much bs.

 

[Swamp Donkey]

The only fuses originally on the truck are for the ABS system. Everything else, including the failsafe module, is on auto reseting circuit breakers. If you're popping fuses you have an ABS problem. The failsafe module is a separate system and would be a separate problem.

 

[skuhler]

The only fuses originally on the truck are for the ABS system. Everything else, including the failsafe module, is on auto reseting circuit breakers. If you're popping fuses you have an ABS problem. The failsafe module is a separate system and would be a separate problem.

I'll have to check that out, then. Someplace there's a short to ground causing the fuse to pop. Where's the most likely place for the ABS to pop fuses?