Two years ago I changed my positive battery cable as it was getting hot. Lately I have been getting a battery light come on in high revs when accelerating hard (it stays off the rest of the time) and I suspect maybe I might need to change the negative cable.
I have a IR thermometer on order with ebay so I can take accurate temperature measurements. Would anyone be able to confirm the following regarding cable / battery terminal temps
1. What a "normal" Working temperature would be in the range of?
2. What a high resistance, defective, cable temperature would be in the range of where it would be necessary to change the cable?

 

Clack, I would say that if your wiring is working properly, you should be within say 10 degrees Celcius of the surrounding temps. So, measure the cable, then measure a support in the area. the 2 read within 10C of each other, probably good.

The other check you can do is using a multimeter, put 1 end of the multimeter on the engine block with the other on the lead of the negative battery terminal (do not touch the clamp of the battery cable). Have a second person start the car and rev the engine up to near redline (preferable to do this with the engine up at temp). If the multimeter goes above 1.0 VDC, then you have an issue. I would personally use a 0.5 VDC standard, but the world standard is 1.0 VDC.