Multilock .040 Terminals (Rover Immobiliser). Help please?

[revilla]

Despite having crimped literally thousands of terminals, these ones always give me trouble. I've recently even cut a plug open for a good look inside but I'm now even more confused.

Anyone got any ideas?

The first problem is that you just can't do them properly with a normal general purpose ratchet crimper, they are too small and need to be crimped very narrow and tall rather than flatter and wider as an (oversized for the job) ratchet crimper does, which means they don't fit the slots in the housing. I've got around this using Molex service pliers to do the conductor and insulator crimps separately at 2.0 and 2.8mm.

These let me make nice neat, narrow crimps.

The terminals now slip easily into the housing and you can feel the latch click into place positively preventing the terminal from being withdrawn. But ...

The face of the terminal is still several mm back from being at the front of the housing and the terminal is hanging out at the back. It all looks completely wrongly placed. They do connect with the male pins on the immobiliser but only just.

The terminals look like this. To the best of my knowledge they are genuine Multilock .040 female terminals.

They have two little tabs sticking out (on the right here) with a little pocket between them. I believe these should slip either side of the locking tongue in thousing which then clicks into the pocket holding the terminal.

These tabs mean that the terminal will only fit into the housing one way around (with the closed back of the crimped portion towards the locking tab and the open side away) so I can't see how they could possibly be in backwards.

This is all in keeping with the drawing I the datasheet:

But this shows the terminals much further inserted as I would expect. So I sectioned a housing for a good look:

 

In this picture the terminals are inserted from the back of the housing on the left. The connector face is in the right. You can see the locking tongues projecting down from the top. But they are a lot further back than in the drawing.

When the terminals are inserted in the orientation shown they lock positively as shown below:

As you can see they are well back in the housing and don't look right at all, especially as they they just overhang the little step in the wall seen in the right which looks as though something should butt up to it.

Intuitively it looks more as though the terminals should be in the other way around.

But the tabs make it completely impossible to assemble this with the housing intact, it still doesn't quite fit (the terminal body is marginally longer that the distance between the face of the housing and the locking tongue) and it is at odds with the datasheet.

I've never yet managed to put one of these plugs together satisfactorily and it is driving me mad!

Can anybody see what I'm doing wrong? Am I using the correct terminals for the housing? The connector is a hybrid with these small .040 terminals and some larger .070 terminals. These are quite a different construction with the tabs on open side of the terminal and fit quite nicely.

Thanks

 

Andrew

[revilla]

Well after all this time it seems as though posting that has focused my mind and I might just have answered my own question!

Looking on RS Components it seems as though there are Multilock .040 terminals:

 

And Multilock-II .040 terminals:

 

... and I think I've got Multilock housings and Multilock-II terminals which aren't compatible. Will order some Multilock terminals from RS and see if they work any better.

[SM25T]

I knew you'd be just the man to answer the question from this tricky OP ! :-)

[revilla]

Hahaha Ian! Yes talking to myself in public again. Wife and kids have finally driven me mad. Well I just ordered from RS and while on there I looked at the larger .070 terminals as well. Seems I have the right series for the large terminals but the wrong series for the small ones, which explains why they look so different and why the larger ones work. Kind of obvious once you've got it.