1991 geo tracker doesn't usually start in colder weather.

[fixkick]

keep and open mind, use the meter and a lamp
here is one case example.
1: pump dead.
2: trying to find why, crazy, hard 29 years of grim on the harness.
3: we find the pump is ok, it's now on the bench and works great, testing in a safe solvent, and a 12vdc battery there or a 12vdc 10amp power supply.
4: so back to the car we go.
5: we attached that head lamp to the 2 wires on the rack ends terminals. (pump still on bench , waiting for future)
6: key turned on , even cranked the lamp or super dim.
7: we use a voltmeter and find the red wire in the pump pig tail shows 10 volts drop from end to end. bingo bad wire.
8: on careful examination we see the wire was chaffed hard by others long ago.
we learn now that there are pin holes in this chafe spot and for years is sucked in water by capillary actions and the natural heating and cooling of wires it sucks in water . (as wires cool they suck water present)
and the copper in the wire is like 1 strand left, and green.
end story, keep open mind,

but the wire with the huge voltage drop is the bad wire if found.