Noid light help

[jpjeep26uk]

Hi, I've bought a noid light to test my Injector. Looked elsewhere on here for help but they are quite old posts so apologies for resurrecting.

Plugged the noid in to the harness and cranked the Jeep, no light.
I've read that light is good and no light is bad ?
The ECU is sending a pulse to the injector out of pin 21 on crank as I've plugged a tester in and it lights up.

Could it be a bad ground wire in/ out of the injector connector?
If so, how do I test that please?

Ive traced it to the OBD 1 diagnostic yellow box but don't know how to test anything to see if it's shorting or faulty?
It's spliced to about 5 other orange wires that head off to different connections, one of which goes through the firewall to the fuse box, but they all seem to be visually ok.

Thanks folks.

 

[dodgerammit]

You need to make sure it's dark when you test as they flash pretty quickly. Close the doors in your shop and turn off the lights. Or if outside, wait for dark. But yes, you need it to flash. It's gonna look more like a bright flicker. They really aren't bright at all.

 

[jpjeep26uk]

You need to make sure it's dark when you test as they flash pretty quickly. Close the doors in your shop and turn off the lights. Or if outside, wait for dark. But yes, you need it to flash. It's gonna look more like a bright flicker. They really aren't bright at all.

Ah ok, I was in bright sunny conditions. Figured it was a bright flash! I'll try again in the dark tomorrow. Thanks for the pointer.