Fuel pump only getting 8V won't start

With the inertia wire connector hooked up?

Yes - that is correct - and what I posted.

How would I test with it connected to the inertia switch? Just strip a short piece then tape it back?

‘Back probe’ each wire - from backside of connector with test light or volt meter lead. It’ll make contact that way.

I'm getting 0V on both. Relay and fuses are good. I did not have a good ground. Retested. .2V on red .1V on green

Disconnect inertia switch wire connector and test again - MUST HAVE ONE of the wires with battery voltage - now the key must be turned off then back on ‘each time’ testing is done! IF neither wire has battery voltage - the FUSE OR RELAY is the culprit! .. Need a helper for testing! ▪️ Does RELAY click on then back off when key is turned on? ▪️

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Relay does click on

I'm getting 1.70V on 1 connection to inertia switch. .02V on the other

Then you should be getting battery voltage at the inertia switch connector! UNLESS a wire is broken from relay to inertia switch.. Make SURE you’re testing voltage at inertia switch connector correctly ! Make SURE you are checking the correct relay. Good luck!

TEST EACH AND EVERY FUSE ON THE TRUCK! See owners manual for fuse box locations - you may have missed the 3rd one. **TEST** ALL FUSES!

I'm going to hardwire the pump to a switch in the cab

CAREFULLY add some fuel (starting fluid) to intake plenum - will engine attempt to start? What I’m getting at is there may be another problem altogether and it is preventing fuel pump operation - as in a blown PCM fuse. I can’t recommend direct wiring to fuel pump but you do as desired.