Causes of corrosion on body ground wires

[DrNick]

I have an ST184 Celica which seems to be plagued with corrosion on many of the ground wires. At first I thought this was limited to the white furry deposits on the battery negative terminal (which i cleaned up and coated the terminal with WD40 to stop it recurring), but it appears to be more severe.

I only really noticed this just now, my rear indicators became temperamental over the last few days and finally stopped working altogether. I pulled the bulbs out and noticed a big mess of white deposits and also a bit of rust on the bulb holders negative. Scratching all of this off made the indicators work for another half a day
They stopped working again when I was out at a friends place and I really am quite partial to having indicators so I took them apart there again. On a whim I tested the impedance between adjacent ground wires (reverse bulb and indicator bulb) and found this was several K. As a quick fix I wrapped a wire around the indicator bulb and grounded this to the chassis which fixed the problem.

I have also noticed the same rusty corrosion ocurring in the interior dome light and I have actually had to replace this unit as the last one completely fell apart as all the tracks had rusted away to nothing.

I am starting to think that its not just the age of the car (1990 model) that is causing these issues and maybe there is something that I should be looking at. Looking forward to hearing what all you techies have to say about it

[oldcorollas]

the furry stuff on battery terminal is often due to leaked acid.

as for the rest of the car, maybe you live in a humid area? bare metal corrodes over time, and salt from sea breezes does not help.