Hv harness test procedure info needed

[ronscantlin]

Has anyone ran across the hv harness test procedure? Is it tested with an ohm meter, or w/12v power applied? Or where can it be sent for testing other than a dealership?

Sponsored

 

[The Weatherman]

@ZSC100

Maybe Zack would know.

 

[ZSC100]

Has anyone ran across the hv harness test procedure? Is it tested with an ohm meter, or w/12v power applied? Or where can it be sent for testing other than a dealership?

When you say "HV Harness" what exactly are you talking about. There are many harnesses in the vehicle.

And why does it need tested?

 

[bmwhitetx]

And why does it need tested?

I think the clue is his profile picture

 

[ZSC100]

Ahhh, no testing needed, just visual inspection and electrical tape as necessary. Even 400v is still "low voltage" there's no reason to be freaked out about doing wiring on the HV (orange) stuff in the truck versus the 12v stuff.

 

[TaxmanHog]

And why does it need tested?

Would a heater module blow the hv harness? Fixed post #47

He is trying the validate the dealer service call that it was the root cause of the failure, and hopefully prove that they threw un-needed parts at the truck at high cost to the owner.

 

[ronscantlin]

Would a heater module blow the hv harness? Fixed post #47

He is trying the validate the dealer service call that it was the root cause of the failure, and hopefully prove that they threw un-needed parts at the truck at high cost to the owner.

This

 

[ronscantlin]

I think the clue is his profile picture

Antimatter blue is cursed. But that’s not the one that needs testing or why. I had another post on here that gives context to the question. Basically, I suspect I got shafted and I’d like to get my suspicions confirmed before further action is taken.

 

[chriserx]

First thing I would do is get the old PTC and resistance test the HV input lines +\-, if the resistance is low that would be a decent indicator they and/or the procedure was fkd. Next I would resistance test the entire harness with a high quality ohmmeter, and cross check the resistances per foot for the cable size using charts like
https://www.engineeringtoolbox.com/copper-wire-d_1429.html
Note that very few people are going to have a precision ohmmeter, and I haven't looked up costs but I suspect they aren't cheap. You are likely looking at a precision of microohms. This is more or less the low hanging fruit of testing. I've built a few ohmmeters using an arduino, but I've never attempted one at that level of precision.

Edit: Also note that a regular high quality ohmmeter may still give you what you need in probing if the resistance in the harness is sufficiently high enough.

 

[ZSC100]

This

Ahhh, ok I do remember seeing in passing in the past, I just went back and read it all.

So, do you have your truck back.

Did you pay the $8k for the harness?

Did they give you the harness?

I have many ideas for how you should proceed, but want to know if you have the harness and have looked it over yourself for visual damage?

 

[chriserx]

I was just thinking about equipment, if you have access to a decent bench power supply that has a constant current mode and a volt meter preferably one with logging, it would go a long way to testing it as well.

 

[bmwhitetx]

This

Context always helps. Suggest next time referring to other threads you posted.

When I read that thread the harness was not the issue. So not sure testing it helps? Wouldn’t your truck still have the new one the dealer installed that wasn’t needed after all? Did they ever give you the old one which I presume is what you want to test?

Have you looked at the WSM or FDRS? Techs usually follow a pinpoint test procedure that ends with a “replace this”. Typically, the service notes they give you outline the step by step procedure they followed. @RLXXI could probably explain better.

So I would also focus on the process (or lack thereof) of the testing they did to arrive at the HV harness being the issue. The dealer may have just been following Ford's procedures so perhaps the blame is on Ford. Can also try getting @Ford Motor Company to reimburse you.

Sorry this happened, unfortunately our trucks are bleeding edge to most dealers and likely the first time they saw this. OTOH, they often over-replace parts on ICE trucks also.

 

[evowner]

Ahhh, no testing needed, just visual inspection and electrical tape as necessary. Even 400v is still "low voltage" there's no reason to be freaked out about doing wiring on the HV (orange) stuff in the truck versus the 12v stuff.

That is a risky statement. 400 volts can stop your heart lickety-split. It can also give you some real nasty burns. It IS VERY DANGEROUS and can be FATAL. Proceed with extreme caution.

 

[TaxmanHog]

That is a risky statement. 400 volts can stop your heart lickety-split. It can also give you some real nasty burns. It IS VERY DANGEROUS and can be FATAL. Proceed with extreme caution.

He is testing the take-off that the dealer swapped out for a brand new one.

All that's needed, is resistance & shorts testing for each conductor in the harness.

 

[chl]

Ditto the above.

An old fashioned multi-meter (on lowest resistance scale) or continuity tested can tell you end-to-end if there is a discontinuity (broken wire) or short (by checking each pin against all the others for a short - zero impedance).

Most likely either a break or a short if the harness is just wire (no other electronic elements in it).

PS: there could be two wires or more that are MEANT to be connected together, like ground wires are sometimes shunted together at one end or the other.

PPS: there could be intermittent breaks or shorts so flexing the cable while testing it could reveal those.

Sponsored