Technical Earth straps

[WitleyPanda]

Where are they all? Want to check condition and contact resistance. Just the main one and the small one to the ECU?

 

[ZaphodB]

Earthing points are all over the car, mostly tucked away inside in the dry.

The most important one is the battery main earth connections to engine and chassis, follow it down from the battery and check each connection point for cleanliness and lack of corrosion. If it looks clean and secure it should be ok.

Checking contact resistance with a multimeter (at a handful of milliamps) isn't a foolproof method of testing at all, you'd be better checking voltage drop ** when under a proper load (like cranking) when there's many amps flowing, any poor resistance in the connection will result in a voltage drop.

** From the only reference earth you can positively (pardon the pun) trust - the negative terminal of the battery. to whatever other thing it's connected to be it the chassis or the engine etc.

 

[WitleyPanda]

Earthing points are all over the car, mostly tucked away inside in the dry.

The most important one is the battery main earth connections to engine and chassis, follow it down from the battery and check each connection point for cleanliness and lack of corrosion. If it looks clean and secure it should be ok.

Checking contact resistance with a multimeter (at a handful of milliamps) isn't a foolproof method of testing at all, you'd be better checking voltage drop ** when under a proper load (like cranking) when there's many amps flowing, any poor resistance in the connection will result in a voltage drop.

** From the only reference earth you can positively (pardon the pun) trust - the negative terminal of the battery. to whatever other thing it's connected to be it the chassis or the engine etc.

It the straps I was concerned with, rather than the small current returns. Having just changed the clutch on the other one I have had opportunity to look all over the engine bay, but did not know if missed one , hidden in plain sight.
I have a proper earth bond tester, but would not use that on a low voltage system, visual inspection should be sufficient, strip, clean, new star/lock washer, etc as appropriate.
This is on second Panda, recently acquired, going through the snagging list. Clearing error codes from Multiecuscan hook up. It has had a new battery, so suspect errors were occurring when last battery died. But checking alternator and straps.