Ford E450 parking brake indicator light

[ljh684]

2018 Ford E450 chassis. The parking brake indicator light stopped coming on when the brake is set. The switch seems OK (white plunger switch in attached photo); if I have the leveler jacks down and release the brake so it pushes the switch plunger, the leveler jacks do their expected auto-retract.

With the vehicle off, when turning the ignition key to "on", the parking brake light comes on momentarily, as do all the other indicator lights, so it isn't a bulb/LED issue.

Any ideas what could cause the indicator light to fail to come on when the brake lever is fully depressed? For example, is there a second "brake is applied" sensor in the parking brake mechanism on the drive shaft that operates the parking brake indicator light, so positive "brake applied" is indicated, rather than just the brake lever being depressed?

I have an appointment with the local Ford chassis dealer a few weeks out.

[ljh684]

Spoke with the service manager, he said the brake indicator is also linked to a brake fluid sensor in the fluid reservoir, so low brake fluid or a bad sensor could cause the light to not illuminate when the brake is set.


Just a note this year 2018 E-450 chassis doesn't have the older "drive shaft parking brake" mechanism sitting on the transmission where it connects to the drive shaft, the cable runs the length of the chassis rearward.

[ljh684]

Ford commercial chassis dealer said the wire tap that Jayco put on the plunger switch lead for the leveling jack emergency retract feature was crimped so hard that it broke the wire inside the insulation, which is why the brake light would only operate intermittently. The circuit was completed for the jack emergency retract, but interrupted from the plunger back into the dash. Parking brake light would only illuminate with the wire in a certain position which allowed the two broken ends to connect.

So the brake indicator was fixed, but Ford said since the aftermarket wire tap crimp broke the wire, it was not covered under Ford. The Jayco dealer sent me to Ford as they said the parking brake indicator in the dash was a Ford chassis issue.


Mechanically, the brake still isn't holding the vehicle when set, so likely the vehicle was driven with the brake on (when the indicator was off) and the brake pads are glazed and will need sanding or replacing.

[ljh684]

Bought some chocks to use while the parking brake was out of commission. Took the rig back to the commercial chassis dealer, they adjusted the mechanical linkage on the parking brake, and it now will hold the vehicle on a slope.


This newer E450 chassis uses a separate drum brake mechanism on each rear wheel, cable activated. Rear wheels are disc brakes for motion braking. Older E350/E450 chassis types used a drum brake parking brake on the drive shaft mounted right behind the transmission. Not sure what year Ford switched to this newer design.

[Dynamo65]

Good information, thanks for posting.