Hello.

1999 Ford Ranger

I want to know of all the ground wire locations so that i can clean them up real good today. My voltage has been reading a little low and i know a lot of the stuff under the hood has corrosion so can you guys tell me where all the ground wires are? Thanks.

 

No, probably not, I doubt if Ford could tell you where they all are, should be yes, lol, but not actual location.

There are 6 locations to check though
Battery negative terminal, never assume, lol
Starter motor bolt, this should be the other end of the battery cable
Head to firewall ground strap, computer and dash ground
Block to Frame ground strap, tail light ground, also fuel pump/gauge in some
Battery to Rad support, usually a smaller 2nd wire on battery terminal, this is for head lights.
Rad support to fender well

You can of course use an OHM meter to test if there is higher resistance in certain parts of the vehicle
remove negative battery cable and attach meter probe to it, then touch the other probe to it to get "0" reading for that meter, now touch the other probe to engine, fender well, rad support, firewall, frame, ect......to see if one has a higher resistance, so a marginal ground

 

If you have a factory wiring manual for your year truck, then the general locations of these ground wires can be had. The factory wiring books give you a location "grid" on a picture of every wire connector, ground, sensor, etc, as well as all electrical wiring, with color codes.

I always buy one of these on EVERY used vehicle I buy that is not under warranty! This, along with the factory repair manuals (factory, not aftermarket) are an absolute requirement to anyone that wants to perform their own maintenance.