The Autonerdz Community Forums - Proper Back Probing Procedure

K-Mech

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Proper Back Probing Procedure
Jul 21^st, 2019 at 9:59pm

Hello, fellow nerdz. I do a lot of harness repair and something just hit me - I see improper back probing every time, and I see it is all publications /videos/conferences that are held by pro auto techs. Most people back probe in a way that damages the weather seal of connectors. If you have never taken apart a connector, you will do something that seems logical but will end up damaging weather seals.

The improper way (but what SEEMS logical) is to back probe into the same hole the wire enters the weather seal. If you do this, you will get a connection, but you will puncture the weather seal and it will slowly tear itself all round as it heats and cools in the engine bay.

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K-Mech Senior Member Picogroup Offline I'm an Autonerd Posts: 216 Nairobi Kenya Gender:	Re: Proper Back Probing Procedure Reply #1 - Jul 21^st, 2019 at 10:04pm The correct way to back probe is to go in between the weather seal and the connector housing.
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K-Mech

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Re: Proper Back Probing Procedure
Reply #2 - Jul 21^st, 2019 at 10:05pm

Sometimes when you insert your back probe, you feel the pin stick and get caught. Most techs force the pin inside when they feel this, and what you will feel is the pin will resist then proceed on as normal. NEVER do this. The reason it gets caught is that the pinhead has entered the crimp area. If you force it in, the pin will open the crimp area and proceed to go in. The unfortunate thing is this will feel very tight and you will get a connection but you have damaged your crimp.

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K-Mech Senior Member Picogroup Offline I'm an Autonerd Posts: 216 Nairobi Kenya Gender:	Re: Proper Back Probing Procedure Reply #3 - Jul 21^st, 2019 at 10:06pm At times you insert the back probe, then feel like its floaty/puggy/ rubbery, and you get no connection. Reason for this is the pin is floating in the area above the crimp.
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K-Mech Senior Member Picogroup Offline I'm an Autonerd Posts: 216 Nairobi Kenya Gender:	Re: Proper Back Probing Procedure Reply #4 - Jul 21^st, 2019 at 10:08pm If you want a good connection, you can do one of two things. Either remove the probe and just go opposite that point of entry (recommended) or push the probe forward (not recommended). If you choose to push the probe forward, you will get a connection at the pinhead itself like so....
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K-Mech Senior Member Picogroup Offline I'm an Autonerd Posts: 216 Nairobi Kenya Gender:	Re: Proper Back Probing Procedure Reply #5 - Jul 21^st, 2019 at 10:14pm But this is dangerous - you may enter like this and spread that contact apart pretty easily.
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K-Mech

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Re: Proper Back Probing Procedure
Reply #6 - Jul 21^st, 2019 at 10:15pm

Finally, some car manufacturers use a very funny type of weather seal that becomes hard like contact cement (I'm looking at you Citroen, Peugeot, you bloody weasels). If you try and rape the connector you will destroy a lot of probes, and if you have a probe strong enough and loaded with viagra, what you will find is after it wins the entry, it will come out with the entire pinhead. In a case like this, save yourself the hassle and just pierce the wire.

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fisher Super Nerd Picogroup Offline Deceased Posts: 2,734 Concord California USA Gender:	Re: Proper Back Probing Procedure Reply #7 - Jul 21^st, 2019 at 10:34pm I stand corrected kmech. Thanks. I have been dipping my probe tips in dielectric grease which I will continue to do.
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Logic LSD Guide Picogroup Offline Posts: 4,147 Bentleigh Victoria Australia	Re: Proper Back Probing Procedure Reply #8 - Jul 22^nd, 2019 at 2:45am fisher wrote on Jul 21^st, 2019 at 10:34pm: I stand corrected kmech. Thanks. I have been dipping my probe tips in dielectric grease which I will continue to do. Fisher, do you think that a bit of lubrication helps you get it in?
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Re: Proper Back Probing Procedure
Reply #9 - Jul 22^nd, 2019 at 5:05am

I absolutely hate and avoid back probing, two reasons
1. Potential for damage
2. An unreliable connection.

Your demonstration only supports my logic, good work by the way......

You will have seen my posts on break out leads that I make, the reason I make those is exactly for the reason that you rightly and generously point out.

Thank you

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Spence LSD Guide Picogroup Offline Posts: 8,025 Jeffersonville Pennsylvania USA Gender:	Re: Proper Back Probing Procedure Reply #10 - Jul 22^nd, 2019 at 5:35am Agreed nice work!
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Re: Proper Back Probing Procedure
Reply #11 - Jul 22^nd, 2019 at 10:25am

In saying I dislike back probing, I must quote an exception, itis a recent one.

A number of new BMWs have the engine control unit in a plastic box in the engine bay.

With the lid off the box one can back probe the terminals of the control units as the plugs are back windowed and one can freely see the unsealed connector terminals from the back side of the plug.

Not withstanding that, work that I'm currently doing on a F02 N57 with DDE7 has a series of 5 pin mcon connectors.

I have been using back probing at the DDE control unit but also have ordered 5 pin male terminal connectors to enablt completion of several 5 pin mcon break out leads.

.

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K-Mech Senior Member Picogroup Offline I'm an Autonerd Posts: 216 Nairobi Kenya Gender:	Re: Proper Back Probing Procedure Reply #12 - Jul 22^nd, 2019 at 7:13pm Logic wrote on Jul 22^nd, 2019 at 5:05am: You will have seen my posts on break out leads that I make, the reason I make those is exactly for the reason that you rightly and generously point out. Please point me to the post or page of what you make.
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Re: Proper Back Probing Procedure
Reply #13 - Jul 22^nd, 2019 at 11:22pm

K-Mech wrote on Jul 22^nd, 2019 at 7:13pm:

Logic wrote on Jul 22^nd, 2019 at 5:05am:

You will have seen my posts on break out leads that I make, the reason I make those is exactly for the reason that you rightly and generously point out.

Please point me to the post or page of what you make.

Your wish is my command......

But only a touch on the number that I have made...so much so storage is an issue

https://www.autonerdz.com/cgi/yabb2/YaBB.pl?num=1556869362

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Bentleigh
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Re: Proper Back Probing Procedure
Reply #14 - Jul 22^nd, 2019 at 11:25pm

By the way sometimes I do not make break out leads, rather I make extension leads with a marked zone in the middle where I will use insulating piercing probes.

I do that so as to not waste construction components on a lead that I may not use that often.

In the event that I use it frequently I can complete it with 4mm banana jacks to a complete lead.

.

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