I think it's time I investigated. My Jeep has started throwing codes for MAP out of range, O2 out of range. Also, different lights (especially ABS and Airbag) sometimes stay on after startup but go out on restart. The radio is also whining with engine revs.

I replaced the MAP sensor, to no effect.

So before I reload the parts cannon, I think grounds should be checked. They're mainly in the same places on RHD Jeeps but the battery ground looks quite sketchy, being just behind the radiator on quite a rusty panel rather than on the inner wing/fender.

To do this, I'm guessing I disconnect the battery, clean up the cable ends and bodywork to bright metal and then do it back up? Is silicon grease a good idea to stop bare metal corroding again?

 

Yes, you generally have the right idea. The grease will slow down the corrosion on bare metal connections, and in the salt belt if I don't treat the connections, they will corrode very quickly. Personally, I don't like to grease the connection surfaces themselves, I tighten things down and then coat the outside with dielectric grease (dielectric just means that it wont carbonize as much when electricity goes through it - has nothing to do with conductivity). Silicon grease would be just fine. Anything that won't hurt the metal and will help block water and oxygen.

Even when treated, I would recommend servicing/inspecting those important electrical connections twice a year (before and after winter).

 

Thanks! I'd better get on it then.