On mine the connector is right above where my right knee is when driving. Pin 1 is towards the firewall. Just jumper 4 and 12 (four pins back from 1 with a paperclip while the light is on and the truck is running.
See Below:
Rear Wheel Antilock Brakes
CODE STORAGE
The EBCM can store only one of 13 diagnostic trouble codes if it finds a fault in the system. If a diagnostic trouble code is stored, you can read it through the flashes of the "Rr ABS" indicator lamp as described below.
NOTE: The diagnostic trouble code is erased from a EBCM's memory every time the ignition key is turned OFF.
NORMAL OPERATION
If the system is operating normally, the "BRAKE" indicator lamp will do the same thing as the "RrABS" lamp during the following procedure. However, always read the "Rr ABS" lamp for consistent and accurate code display and diagnosis.
CONNECTOR LOCATION
Data Link Connector (DLC)
The data link connector (DLC) is located behind the instrument panel driver lower LH side.
READING DIAGNOSTIC TROUBLE CODES
With The Ignition ON:
Diagnostic Trouble Codes (DTCs) can be read by jumping terminal "12" (diagnostic terminal) to terminal "4" (ground) of the data link connector (DTC).
If the lamp does not light, see Chart A under DIAGNOSIS WITH OUT TROUBLE CODE.
If there is no diagnostic trouble code stored, the lamp will go off and stay off when the jumper wire is removed. Refer to DIAGNOSIS WITHOUT TROUBLE CODE.
If there is a trouble code stored, the lamp will begin to flash when the ground is removed. Go to Step 2.
Reading Flash Code - (Example Code 3)
Wait for a long flash, then count each short flash and the last, long flash. The total number of flashes gives you the diagnostic trouble code.
GETTING THE CORRECT CODE
The EBCM may be in mid-count when you first ground the diagnostic lead. Let the lamp flash its sequence several times to be sure you are counting the right number of flashes. Wait for a long flash for an accurate total.
Proper Ground
If you cannot make a consistent, accurate flash count, make sure you are just briefly grounding the lead and then removing the ground. The "Rr ABS" lamp will light steadily whenever the lead is grounded, so the ground must be removed completely to get an accurate count of the flashes.