Wiring leccy help please

[brickwall]

On testing the wiring loom to the ecu and MAF and  I'm getting some very low voltages on some wires.

 

I'm getting an open circuit on the gear select resistance. I'm thinking it may be fusible links.

 

How do I test fusible wire links, I'm not too good with the leccy witchcraft stuff.

 

Do these look burnt or knackered?

 

 

 

[AMC Rebel]

Fusible links are supposed to act like fuses - either they work or they have blown, so testing is yes/no. Low voltages in injection/ecu circuitry can be normal depending what it is and what it's doing, and how it's getting measured.

[PiperCub]

^^ As above, a fuse or fuseable link is either dead or alive so don't think that's the problem. Low voltage issues are often the battery, if you check it open circuit it'll seem healthy but put some lad on it then the terminal voltage can take a serious dive depending on condition/age so I'd test the battery first, pref with a load or drop tester. I think most auto-sparky's would start with the battery too. 

 

Otherwise low V's tends to be bad connections which are either damaged by contamination (oil, fuel, water etc) or corroded which makes for high resistance so you get a voltage drop. 

 

Check what voltages you are actually supposed to be seeing, it's not always black and white, not always nice and neat +5V or +12V etc.,  so you may be reading correctly. In my experience it invariably the connections that are the problem, it is seldom the ECU, sensor etc. esp. on older cars.

 

BTW - in answer to your last question, doesn't look bad to me, I've seen way, way worse that's still (miraculously!) working - not just in cars either. 

[brickwall]

Okay I'll have a deeper look today. Thanks guys.