This 2005 Ford Ranger came in with the complaint that the instrument cluster would stop working sometimes. Recently it had gotten to the point that it did not work at all. When the gauges do not work when the key is first turned on the transmission gear selector also could not be moved. In order to move the vehicle the key has to be rotated forward but not enough to power on anything. The shifter can then be placed in neutral so that the engine can be cranked. Safety first though. Set the parking brake and hold the brake pedal down.
I took a quick look and the stoplights did not work. There was no power at the stoplight switch. A check of the fuses found that fuses 19, 28, 29, 32 & 33 do not have any power at all when the condition was present.
Power to all of these fuses originates at fuse number 3 in the underhood fuse box. It was both good and powered.
Power comes from the underhood fuse box to the interior smart junction box via a dark blue wire. I spotted a fairly large dark blue wire in the vertical (brown) harness connector. I flipped the locking lever up as shown in the picture and worked on wiggling the harness connector out of the SJB.
I am fairly sure I found the problem. Water had gotten into the harness connector and the SJB causing corroded terminals and loose connections.
Waiting to see how the customer wants to proceed. The most correct repair option would be to replace the SJB and the wiring harness along with locating and repairing the water leak.
1 (5A) – Instrument Panel Dimmer Switch
2 (10A) – Trailer Tow Park Lamps
3 (10A) – Right Low Beam Headlamp
4 (10A) – Left Low Beam Headlamp
5 (30A) – Windshield Wipers/Washer
6 (10A) – Radio (Run/Accy)
7 (5A) – Headlamp Illumination Indicator
8 (10A) – Restraints Control Module (RCM), PADI (Passenger Air Bag Deactivation Indicator)
9 (5A) – Cluster Air Bag Indicator
10 (10A) – Cluster (Run/Start), 4×4 Module (Run/Start), Tire Pressure Monitoring System (TPMS) (Run/Start)
11 (10A) – Smart Junction Box (SJB) (Logic Power)
12 (15A) – Center Console Subwoofer Amplifier
13 (15A) – Horn, Interior Lamps
14 (15A) – High Beam Headlamp, High Beam Indicator (Cluster)
15 (N/A) – One-Touch Down Relay
16 (30A Cartridge Fuse) – Power Windows
17 (15A) – Turn Signals/Hazards
18 (N/A) – Not Used
19 (20A) – Center High-Mounted Stop Lamp (CHMSL)/Stop Lamps
20 (10A) – Anti-Lock Brake System (ABS) Module, Brake-Shift Interlock, Speed Control Module, Back-Up Lamps, Overdrive Cancel Switch, Electronic Flasher (Turn/Hazard)
21 (5A) – Starter Relay
22 (5A) – Radio (Start), 4×4 Neutral Sense (Manual Only)
23 (30A) – Headlamps (Low and High Beam)
24 (20A) – Radio
25 (N/A) – Accessory Relay
26 (2A) – Brake Pressure Switch
27 (10A) – Climate Control Blower Relay/Blend Doors, 4×4 Module
28 (15A) – 4×4 Module B+
29 (20A) – Cigar Lighter or Power Point, Diagnostic Connector (OBD II)
30 (5A) – Power Mirrors
31 (20A) – Front Park Lamps, Rear Park Lamps, License Plate Lamps
32 (5A) – Brake Switch (Logic)
33 (5A) – Instrument Cluster, TPMS Module
34 (20A) – Power Point
35 (15A) – Power Locks
The customer decided to move forward with repairs but we decided to try and salvage the SJB by cleaning the terminals. I used a small screwdriver to scrape the corrosion from the terminals.
I searched for a new connector or at least new terminals but was not very successful. In the end I found a good used connector at a local salvage yard. The covers and …
… terminal retainers have to be removed in order to transfer the terminals from one connector to the other.
With the white terminal locking plate removed it is pretty easy to see the green film on the lower terminals.
I made sure that I took this picture so that I would know the wiring order for the wires I needed to splice.
The new used harness connector. It appears the the connector will be in 2005 through 2011 Ford Rangers.
The transfer of wires begin.
The connector and damaged wires successfully replaced.
I added some silicone grease to the connector on the lower half where the water had gotten into the old connector.
All installed and working the way it should. I looked for where the water had been coming in and it seems to enter from the cowl area and then it barely wicks through the foam seal where the air inlet box attaches to the firewall. From there is drips on the two vacuum lines, runs down hill to their lowest point where it collects and falls onto the brown connector.
I recommended having a body shop look at it for a permanent solution. In the meantime I cut a piece of plastic sheeting and made a water shield (not shown) to protect the SJB and wiring from water intrusion.