SOLVED New immobiliser. Issue with wiring..cannot fathom why

[thecyrusvirus]

So, I have got the immobiliser wired up to the point where I can enable and disable it.

It has two built in relays to cut 2 circuits. These show no continuity with the immobiliser armed and then continuity with it disarmed as I would expect.

I have tried breaking into a few different wires to immobilise the van and the behaviour of the relays is the same. However, the van will not start with even just one of the immobiliser breaks wired up.

Checking the continuity either side of the break proves the immobiliser arms/ disarms but no joy with starting.

If I remove the immobiliser from the equation and splice the original wires back together then all works fine.

I don't want to put too many specifics here but wanted to see if anyone had encountered anything similar before.

Any help welcome as I have been left completely befuddled!

[syncronized]

Where have you taken the supply for the immobiliser from?

[thecyrusvirus]

I have a switched live from the back of the fuseboard and another from the main loom behind the dash. Then a permanent live from the connector behind the ignition switch barrel.

Tested and the switched lives are on and off correctly with the key and the permanent live is always on.

I figured that as the circuits are making and breaking correctly with the immobiliser arm and disarm I must have got most of the wiring right!

Could a dodgy live cause this sort of problem then?

[syncronized]

Possibly. Have you tested to see if the permanent live is actually live whilst cranking the engine over?

[thecyrusvirus]

I will have to grab an assistant tomorrow to turn the key whilst I put the meter across it and report back once tested

thanks for taking time to reply

[syncronized]

To eliminate that area of doubt you could always run a temporary permanent live straight from the battery just to see if it cures the problem

[thecyrusvirus]

Good thinking. I will try that when I get back from work tomorrow and see if it helps.

[syncronized]

Best of luck with it. Let us know how it goes

[thecyrusvirus]

Ok

So it was a combination of one of the switched lives dropping below 9v when cranking and the other one going to 0v when cranking! Doh

Now all wired in with 2 circuits being interrupted and it behaves as it should

Thanks for your help syncronized, I was tearing my hair out yesterday. I even ended up fitting my tracker that has been sitting in a box for 2 months.

All wires now covered in heatshrink and hidden in the loom before loom taping it all up out of the way.

Jobs a good un

[syncronized]

Glad you managed to sort it