Wideband wiring - car doesn't start with it connected

[tez]

Hi guys

I've fitted an AEM UEGO wideband to my car but for some reason the car won't start with it connected. I've got a Toad Sterling Excel immobiliser which lets the fuel pump prime once it sees the fob. With the wideband connected, the fob isn't recognised and turning the key does nothing at all.

I've earthed it on the cigarette lighter brown wire, and connected the switched live to the yellow/black wire from the heated rear screen switch. The gauge comes on as it should when you flick the key to the first ignition position.

Any ideas? Thanks

[cheys03]

What happens if you disconnect the wideband, turn the heater switch on, then try to start the car?
What happens if instead of the wideband, you put a load (say a small bulb) in the circuit between the heated rear screen switch and lighter earth?
Does the immobiliser still see a good 12v+ with the gauge or test bulb connected?

[tez]

Cheers for the tips I've wired it to the other side of the switch for now just so I can diagnose my running issues but will check those out when I get chance. The car still doesn't start if the switch is on when you try turning the key though :s