Hi I have a 94 dodge ram van B250 and have an ABS light on, the previous owner had kindly unplugged the warning lights so I didnt know when I bought it.
I understand I can earth the black wire on the diagnostic port to read the ABS fault codes but cant find the port...can anyone help and perhaps post a pic of the port.
I did find one under the hood to the right of the ECM but for some reason the black wire was constantly earthed...assume to disable the faulty ABS...perhaps someone can help please?

 

When you turn the key to ON all light will light up so you can see if any are not working. With it disconnected you should've questioned the owner as to why the ABS light didn't come on when the key was turned to ON.

 

Going by my '95 manual, the engine data link connector is C136 (6 pin) and is on the cowl panel above the PCM.
This is not what you're looking for. Here's what you need:
DIAGNOSTIC FAULT FLASH CODES
The microprocessor in the electronic control module has a self test feature. This feature is activated
whenever the ignition switch is in the On and Run positions. If a system fault is detected, the control module illuminates the antilock light and stores the fault code in the microprocessor memory. If a fault code is generated, the module will retain the code after turning the ignition switch to Off position.
System faults are identified by a series of flash codes that operate through the antilock warning light. Temporarily grounding the antilock diagnostic connector will produce the flash code sequence. Refer
to Fault Code Identification in this section.
FAULT CODE CAPACITY
The microprocessor memory will store and display only one fault code at a time. The stored code can be
displayed by grounding the antilock diagnostic connector.
RWAL DIAGNOSTIC CONNECTOR
Connector Location
The RWAL diagnostic connector is at the left side of the steering column near the parking brake release
handle. The black, 2-way diagnostic connector has only one wire attached to it. This is the 20 gauge black with white tracer wire from test terminal 12 on the control module. The RWAL diagnostic connector is plugged into the data link wire connector.
How To Generate Flash Codes
Flash codes are generated by momentarily grounding the diagnostic connector black wire and counting the warning light flashes. (a) Unplug the data link wire connector from the RWAL diagnostic connector. (b) Momentarily ground the RWAL diagnostic connector black wire with a jumper wire (maintain ground for about 2 seconds). (c) Immediately note and record the number of flashes at the antilock warning light.
FAULT CODE IDENTIFICATION
When a fault code is generated, the red brake warning lamp will also illuminate. To determine what the fault code is, momentarily ground the diagnostic connector and count the number of times the antilock indicator lamp flashes. Fault codes and typical malfunctions are outlined in Figure 6. The initial flash will be a long flash followed by a number of short flashes. The long flash indicates the beginning of the fault number sequence and the short flashes are a continuation of that sequence.
You must count the long flash along with the
short flashes for an accurate fault code count.
CLEARING A FAULT CODE
To clear a fault code, disconnect the control module connector or disconnect the battery for a minimum of
five seconds. During system retest, wait 30 seconds to be sure the fault code does not reappear.