Old school only!! Wiring harness testing?? | Ford Explorer Forums - Serious Explorations

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Old school only!! Wiring harness testing??

Exploder321

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City, State
Norfolk, VA
Year, Model & Trim Level
2001 Explorer Eddie Bauer
I'm challenged testing the wiring harness on my 01 Eddie Bauer 5.0 😑. For my '93 Bronco, I have a 'break-out box,' which connects to the wiring harness where it connects to the PCM allowing circuit and resistance testing of all the engine sensors and electrical components (description is for the youngsters). Is there such an animal for an '01 5.0? 🤔
 



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I'm challenged testing the wiring harness on my 01 Eddie Bauer 5.0 😑. For my '93 Bronco, I have a 'break-out box,' which connects to the wiring harness where it connects to the PCM allowing circuit and resistance testing of all the engine sensors and electrical components (description is for the youngsters). Is there such an animal for an '01 5.0? 🤔
It appears the 2001 PCM is a 60 pin? Is that correct?
If so, do you still have the breakout box that you used on your 93?.
 






The interfaces are different, the pins on the Bronco ECM (EEC-IV) are hollow and abt 1/16" , the 01 has solid pins abt like a sewing needle thickness, and more of them. It seems most diagnostics plug in via the port below the steering wheel anymore. I'll have to go pin to pin - the guard comes out of the plug at the end of the wiring harness, though I hate to poke around in there risking damage. Maybe if I can find an adequate probe to use with the plug and connect the multimeter to that.
 






The interfaces are different, the pins on the Bronco ECM (EEC-IV) are hollow and abt 1/16" , the 01 has solid pins abt like a sewing needle thickness, and more of them. It seems most diagnostics plug in via the port below the steering wheel anymore. I'll have to go pin to pin - the guard comes out of the plug at the end of the wiring harness, though I hate to poke around in there risking damage. Maybe if I can find an adequate probe to use with the plug and connect the multimeter to that.
They sell a breakout box for the ODB 2 under the dash 16 pins. There should be a adapter available but not cheap.
My 95 (ODB1) has a 60 pin at the PCM. I have not try too connect it too the breakout box (ODB1).
 






96+ are 104 pin obd2 pcm connectors
those old breakout boxes are cool!!

What are you wanting to accomplish here? You could simply do a continuity test from each pin at the pcm to the destination wires on the other end of the harness
 






Same question, what are you wanting to accomplish? I just wait till there's a problem then look at what the potential causes and circuits for it are.

Attached is the pinout for a '99 5.0L if it helps.
 

Attachments







96+ are 104 pin obd2 pcm connectors
those old breakout boxes are cool!!

What are you wanting to accomplish here? You could simply do a continuity test from each pin at the pcm to the destination wires on the other end of the harness
That's pretty much it, continuity and possibly a load test. Either the wire's gone bad or the part of the PCM providing the signal to the coil to fire is no good. I'm hoping it's just the wire, the PMC was replaced with an Autozone BlueStreak reman a few months ago. An old school break out box would provide for remote testing of sensors, which would be handy. This rig is 22+ years old, most of the engine sensors have been replaced at this point.
 






Same question, what are you wanting to accomplish? I just wait till there's a problem then look at what the potential causes and circuits for it are.

Attached is the pinout for a '99 5.0L if it helps.
I have a misfire on the drivers side coil, need to isolate the cause (I don't think it's the coil, it only has 10 min of run time on it), its either the wire or the PCM. Thanks for the pinout, been looking for one. Ordered the Ford shop manual DVD of ebay the other day, should arrive Thursday.
 






^ Single cylinder misfire or two cyl? It's a waste spark system so PCM control line to coil, or coil, plug or wire, should cause two cylinders to misfire. If a single cylinder, I'd sooner suspect wiring to or a fuel injector itself, if not something more serious.

There's 2nd gen wiring diagrams linked in my sig, but for the 5.0L, more info in the Helms link on that post. It is for a '99 but I doubt much changed.

Along with checking continuity of the wire between the PCM and ignition coil module, you can also use a multimeter to measure for voltage blips on each respective wire to the module, wire colors and corresponding cylinder #'s shown on the Helms diagram in section 21-1. Compare suspect coil for the cylinder(s) in question to the other 3 coil signal wire readings.
 






^ Single cylinder misfire or two cyl? It's a waste spark system so PCM control line to coil, or coil, plug or wire, should cause two cylinders to misfire. If a single cylinder, I'd sooner suspect wiring to or a fuel injector itself, if not something more serious.

There's 2nd gen wiring diagrams linked in my sig, but for the 5.0L, more info in the Helms link on that post. It is for a '99 but I doubt much changed.

Along with checking continuity of the wire between the PCM and ignition coil module, you can also use a multimeter to measure for voltage blips on each respective wire to the module, wire colors and corresponding cylinder #'s shown on the Helms diagram in section 21-1. Compare suspect coil for the cylinder(s) in question to the other 3 coil signal wire readings.
J_C, thanks! All the problems are in the thread below, there were several, now down to a single P0352 code. It had a P0303 and P0305, which might come back if I ran it long engough, I'm hoping not to burn up the new coil.

2001 Explorer 5.0 P0174 Code

It was missing on cyl #3 and 5, same coil (drivers side), no spark at the coil. I'll do what you described above probably Saturday, and report back.
 






If it gave you a
Misfire code in 10 min of run time I would suspect an injector

It is more difficult for the computer to identify a misfire through the ignition would usually take longer then 10 min unless there is a circuit issue

What was the code
 






If it gave you a
Misfire code in 10 min of run time I would suspect an injector

It is more difficult for the computer to identify a misfire through the ignition would usually take longer then 10 min unless there is a circuit issue

What was the code
P0352 - I just replaced the fuel injectors last week, along with connectors and new intake gaskets. I'm testing the wires from the PCM to the coil on Saturday.
 






You replaced all of that chasing this code?
 






Circuit failure I would think perhaps the coil pack is bad or issue w wiring so you maybe on the right track. Do you have the firing order correct? This 01 5.0 is in your 93 fsb?
 






There were several failures, to include the EGR valve, EGR solenoid, identified vacuum leaks around the plenum... The mechanic thought it was the injectors (I thought in the long run it was a good idea to replace, the connectors were very brittle as well). It's possible one is bad, haven't tested them - if they're good I may have them cleaned and put them in my '93 Bronco.

The shop manual DVD showed up yesterday, a treasure trove of information, with test steps to isolate a problem, it's looking like the wiring, hopefully not the PCM (that is a reman put in a couple of months ago - old one fried by the EGR solenoid).
 






Yikes!!

Was any of the factory wiring modified?
 






Same question, what are you wanting to accomplish? I just wait till there's a problem then look at what the potential causes and circuits for it are.

Attached is the pinout for a '99 5.0L if it helps.
J_C, the diagram is looking at the face of the PCM, right? Same as looking at the back of the connector?
 






^ As far as I know it is, but you might also be able to compare the wire colors on the connector, to those on the diagram, or check continuity on the wiring harness connector pins 24 and 25 to vehicle power ground & chassis ground.
 






Upon closer inspection of the back of the PCM Connector, the pins are inverted from the diagram posted by J_C - the convention being that the technician would twist the connector so as to face the front of the vehicle to have the same orientation as the diagram, the left and right sides of the connector back are marked as follows:
79 ..............104
53 ............... 78
27 ............... 52
1 ................. 26

The mystery of the failed continutiy checks is solved. Now to check the correct wires...
^ As far as I know it is, but you might also be able to compare the wire colors on the connector, to those on the diagram, or check continuity on the wiring harness connector pins 24 and 25 to vehicle power ground & chassis ground.
 



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