E-450 intermittent cruise control problem solved
Posted: Tue Jan 08, 2019 10:00 am
We had an intermittent cruise control problem for several years on our 1999 Ford E-450. Ours is a 7.3 diesel, but most of this will also apply to the V-10. The cruise would occasionally stop working after being activated and recently progressed to not working at all. I read the shop manuals. Since the van is drive-by-wire, there is no servo slave to fail on the throttle (it runs fine without cruise) and everything is controlled by the PCM. The only circuits are the steering wheel buttons, brake light switch on the brake pedal, emergency brake activation switch, and for redundancy, a hydraulic pressure switch on the master cylinder.
I gave the PCM a temporary pass because everything else works fine.
The steering wheel buttons tested fine.
The brake light switch on the brake pedal tested fine.
The emergency brake activation switch tested fine.
The wire to the emergency brake activation switch shorted to ground and that was assumed to either be the problem or that it is grounded in the PCM--I gave it a temporary pass.
The hydraulic pressure switch on the master cylinder was under a recall from Ford. I took the van to the local Ford dealer with the recall letter several years ago hoping it was the problem for the intermittent cruise control problem. The wonderful mechanics at the dealership informed me that the van had no hydraulic pressure switch to replace and that it must have been a factory error with the recall notice.
I unbolted the radiator pressure reservoir and moved it aside for a better look at the master cylinder. Sure enough there is a pressure switch. It didn't appear to be leaking brake fluid (the reason for the recall), but I did notice some green on the over-stressed sensor wire. The plastic tape and wire insulation were cracked and the copper wire was corroded to green dust. I soldered in a replacement link of wire and the cruise now works fine again.
On a side note, my favorite diagnostic and programming tool to use on a Ford is FORScan software: either the FORScan Lite app on a phone or the full downloadable version on a windows notebook computer. (I used the FORScan Lite app on a phone to test the cruise circuits.) The software requires a good bluetooth module to plug into the OBDII port.
ScanTool OBDLink MX Bluetooth:
https://www.amazon.com/gp/product/B006NZTZLQ
https://forscan.org/home.html
Chuck
I gave the PCM a temporary pass because everything else works fine.
The steering wheel buttons tested fine.
The brake light switch on the brake pedal tested fine.
The emergency brake activation switch tested fine.
The wire to the emergency brake activation switch shorted to ground and that was assumed to either be the problem or that it is grounded in the PCM--I gave it a temporary pass.
The hydraulic pressure switch on the master cylinder was under a recall from Ford. I took the van to the local Ford dealer with the recall letter several years ago hoping it was the problem for the intermittent cruise control problem. The wonderful mechanics at the dealership informed me that the van had no hydraulic pressure switch to replace and that it must have been a factory error with the recall notice.
I unbolted the radiator pressure reservoir and moved it aside for a better look at the master cylinder. Sure enough there is a pressure switch. It didn't appear to be leaking brake fluid (the reason for the recall), but I did notice some green on the over-stressed sensor wire. The plastic tape and wire insulation were cracked and the copper wire was corroded to green dust. I soldered in a replacement link of wire and the cruise now works fine again.
On a side note, my favorite diagnostic and programming tool to use on a Ford is FORScan software: either the FORScan Lite app on a phone or the full downloadable version on a windows notebook computer. (I used the FORScan Lite app on a phone to test the cruise circuits.) The software requires a good bluetooth module to plug into the OBDII port.
ScanTool OBDLink MX Bluetooth:
https://www.amazon.com/gp/product/B006NZTZLQ
https://forscan.org/home.html
Chuck