Hello, I’m trying to assemble a Molex connector, like this one:

But I have issues with it, because the crimp terminals won’t snap into place inside the housing. I’ve never assembled a Molex connector before, so I don’t know what to expect. Should I insert the female crimp terminals inside the female or male housing? How hard does they snap in place? Am I inserting them wrong? Am I using the wrong crimp terminals? Obviously you can’t answear that, but I’m just trying to figure out what could be wrong, because something seems wrong.

 

What you show is female in male enclosure. Generally, that is called female (i.e., the gender is determined by the contact, not the shroud). Contacts insert from the back. There are lots of variations and sizes.

Do you know the specific Molex part numbers? One problem people have is properly crimping the wire to the contact. Too broad/big a crimped area will not insert properly. A picture will help, but I suspect that is the problem. Is the wire the correct size or only slightly smaller? They generally insert quite easily with a very slight click when the barbs engage.

 

You could be crimping them the wrong way, or maybe inserting them the wrong way. I've worked with Molex connectors before, and they shouldn't be hard to work with. As John's said, the Molex part numbers that you acquired would come in handy for us to help you. Also a pic or two of the terminals and enclosures would be most welcome.

 

43025-0600 - Micro-Fit 3.0, Receptacle Housing, 6 Poles, 2 Rows, 3mm Pitch, Molex (with 43030-0010 - Crimp Terminal, Female, Tin, 30 ... 26AWG, Molex) and 43020-0600 - Micro-Fit 3.0, Plug Housing, 6 Poles, 2 Rows, 3mm Pitch, Molex (with 43031-0007 - Crimp Terminal, Male, Tin, 24 ... 20AWG, Molex).

I’m using 28 awg wire with ~ 21 awg insulation for the female crimp terminals 30-26 AWG, (which length of wire should be inserted into the crimp terminals?) My male crimp terminals is 24-20 AWG, and I’m using a 20 AWG wire with ~15 AWG insulation.

Could the difference between the female and male crimp terminals be an issue?

I’m not using a crimping tool though, just a plier. But I haven’t hade any issues with the crimping connection really, it seem strong. The issue I’ve had is associated with inserting the crimp terminals into the housing.

 

Use a Hozan crimper. It's about $70.00 USD. I'll need to look up the right p/n.

The issue I’ve had is associated with inserting the crimp terminals into the housing.

Yep, because you have a non-symetric square peg that wont fit into a round hole.

The removal tool BTW is a hollow tube.

The crimp terminal has two crimps that need to be made. One for the wire and one for the insulation.

The insulation crimp makes a round circle around the insulation. You won't pull that off with plyers.

The wire crimp folds the terminal into a heart shape onto the wire. The heart-shape basically collapses on the wire.

 

I realized what I was doing wrong - I was inserting the wrong crimp terminals into the wrong housing. It works now and they snap in place. Crimping with a tweezer and a plier obviously isn’t recommended, it’s time consuming and the result usually is less than ideal.

 

I don't have a crimping tool, I always solder the terminals I use. That practice has avoided me countless headaches over the years.

I'm glad to hear you've solved your problem.

 

"Usually" it's the male pin in the female housing and the pin type defines the sex. For CPC connectors this is called Rev-sex, but there is also a Same-Sex version where the female pin is in the female housing. The industry likes plug and receptacle, not male and female.