| PM | Quote | Reply | Full Topic |
Joined: Tue Dec 5th, 2017
Location: Michigan, USA
Posts: 118
Status:
Offline
Reputation: 
Reputation Points: $user_rep
C1939 is for an electrical problem in the Deactivator Switch (Brake Pressure Switch) circuit. The DS screws into the front of the brake master cylinder and is involved in the operation of the speed control (many Ranger years) and the ABS (2001~2003 Ranger only).
The Deactivator Switch was subject to recall for 2001MY Ranger as well as several other model years and also other Ford vehicle lines. In service, the diaphragm in the OE Deactivator Switch may rupture and leak conductive brake fluid internally onto the switch contacts, thus providing a path to ground through the fluid in the brake master cylinder . Worst case scenario is overheating of the flammable fluid leading to a vehicle fire. Depending on the year and vehicle line, this can even happen when the ignition switch is in the "OFF" position and the vehicle has been left unattended for several hours or days.
The recall repair for 2001 Ranger consists of a replacement Deactivator Switch (from a different vendor) and a small patch harness which contains a dedicated 2A fuse for the DS circuit. (2003 and later Rangers had the fused circuit integrated into the original harness and fuse panel.)
If the recall action has not yet been performed, I would start by having it done immediately (Recalls stay in effect indefinitely).
If the recall has already been done, I would first check the condition of the patch harness connectors and fuse. Then move on to the Deactivator Switch itself.
____________________
2003 FX4 Level II, Supercharged 5.0L V8, Headers, Duals, BW4406 manual T/C
Aussie Locker, Torsen L/S, 4.10's, Bilstein 7100 rezzies, Cadillac/Mustang rear discs, Duff traction bars
Keypad Entry, Lock LEDs, sway bar discos, Heated seats, Explorer EATC, Trip Computer and consoles
Other rides:
2016 C-MAX Energi (plug-in Hybrid)
2011 Taurus SEL (highway cruiser)
2003 Ranger 2.3L M5ODR1 Regular Cab (drudge)