Early '92 ALDL Pin layout.

[femurphy77]

Can anybody provide me with a directory of what each ALDL pin is for. I'm trying to troubleshoot a cooling fan issue but my preliminary Service manual pin layout does not show a pin for the cooling fans. When I short A-B I get the air pump to come on as well as of course the flashing engine light reading out any codes. I am a little leary of indiscriminate grounding of the pins as I would really hate to fire the airbag. Being an early '92 perhaps I need this information for a '91 for accuracy, it is #606 of the production run. Thanks for any assistance. Frank Murphy, Indy

 

[Jeffvette]

Your ground is always going to be the "A" terminal

B ECM
C Selective Ride Control
D Blank
E Blank
F TCC for L98/LT1
G CCM Diagnostics
H ABS
J HVAC
K Supplemental Inflation Restraint
L SIR Serial Data
M Serial Data

The Coolant fan is turned on and off by the ECM based on inputs from the coolant temp sensor, VSS. Battery voltage is applied at all times to terminal "E" of the coolant fan relayand when the ignition switch is in "run" , battery voltage is applied to terminal "D" of the relay.

 

[femurphy77]

Thanks for the quick response. I have found a few other discrepancies in the prelim service manual I have. I have been cross checking with a chiltons but of course you know if we need more than a firing order it isn't much help. Frank Murphy