Hi everyone...newby here...I have a Mex Strat (present from the Wife)..changed the pick guard today and now I have no bottom pickup..
everything looks good..just nothing working on the lower end..
Any ideas?

Welcome.

There are sliding contacts in the selector switch. Make sure they are engaging when you choose the bridge pickup. Also, make sure there is no dirt or debris on or in these contacts and that there are no errant strands of wires just hanging around near the switch's contacts or the bride pickup's terminal on the switch. Check in between the eyelets of the bridge pickup's lead wires and the lower tone pot's wire to the switch terminal for errant strands too.

If none of the above resolves your situation, you'll have to test the pickup itself for continuity.

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You dig?

Yeah, look at the selector switch and see if a pickup wire broke off while changing the PG (white and yellow wires). Or one of the black pickup wires that connects to the back of one pot could have broken off. Trouble is, you'll have to remove the PG again to check.

.

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---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.