Where is diagnostic plug on 1994 ford explorer?

Answer 1

There is a Diagnostic plug behind the Fuse block on the passenger side of the vehicle under the hood but you'll need an obd-1 scanner or you can do a self diagnostic with by jumpering it with the STI "Self test input" you'll need a jumper wire and an Analog Volt meter the one with the needle NOT DIGITAL , This is a little tricky but easy enough to do, The STI Plug is a single slot plug and the Test Block has 5 slots Both are covered with a black lid and possibly attached to the inner fender or free hanging by the firewall,, To do the test have the Ignition in the off position and jumper the Single slot STI plug to the 6 slot test plug, The test plug has an almost totally flat bottom and a slightly peaked top Looking at the plug with the Flat side on the bottom there will be 2 slots on the top and 4 slots on the bottom the jumper wire will go into the top right input slot I'll do a diagram if I can

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___________ Crude but it'll look like that Jumper to the one with the O instead of a Dash That's the Hard part even tho it's simple once you look at it, Your analog volt meter will be grounded to the battery and the Positive Lead will need to be in the X position The X in my crude diagram that is then all you do is turn the key to on but DO NOT start the Truck and it will go into Diagnostic mode and Start spitting out codes so have pen and paper ready The First code ohh and you read the code by watching the needle on the volt meter, the First code will always be 111 with a full second in between each then it'll spit out other stored codes if it only Gives you 111 twice it means all pass if it gives you a 3 digit codes after the 111 it'll be quicker less then 1/4 sec between pulses so if you got a 312 error code it would look like this with the needle moving "PULSE PULSE PULSE Pause 1/2sec Pulse Pause1/2sec Pulse Pulse Pause 2 full seconds then on to the next code if there are any more If you get Lost in the codes just turn the key off for 10 seconds then back on and it'll start over PS If the diagram doesn't come out right the Positive lead will go to the 2nd to the left slot on the bottom 4 and the sti plug will jumper to the top right slot there are only 2 slots on the top Good Luck