Electrical Woes

[Pdxguy77]

My 90 Ranger is plagued by electrical gremlins. Im pulling my hair out (whats left of it). ok......so

New Battery
New Alternator
New Ground Wires to frame, motor, firewall, hood
IAC pulled, cleaned and tested
Did continuity tests all passed

When my heat and lights off everything runs great, heat on when brakes applied, 1/2 to 1 volt drop without coming back up. turn on lights and heat when brakes applied ill drop 2 to 3 volts without it coming back up. Ill have the same problem when im in reverse with lights and heat on and brakes not applied. I did notice my main power wire coming off my starter relay to my maxi fuse block is pretty corroded but it passes continuity tests.

I have installed a relay inline with my low beam head lights which only gave me a gain of 1/4 volt.

Im open to suggestions


Thanks

 

[TUNDRATREES]

Just because your wiring passes contituity tests does not mean it will handle any amps. If it looks corroded where you can see, just think about where you can't. Replace it first and go from there.

 

[holyford86]

Just because your wiring passes contituity tests does not mean it will handle any amps. If it looks corroded where you can see, just think about where you can't. Replace it first and go from there.

Continuity tests use a very low amount of current, they don't tell you the amperage capacity of a given piece of wire, Looking at voltage drop across certain wires will give you a better idea of where your bottleneck lies.