I Have an Infestation
 

My truck was sitting for 4 years and I finally got to fixing it. I've these fucking rat's and field mice in the truck for god knows how long now. They chewed through my seat belts, which I fixed, and almost chewed my registration papers. They've now chewed through my rear seat belts. I have no clue where they are but I've left a roll of paper towel in the front seat and now there's pieces of it all over the front but the the roll is in the back now. I've tried poison, glue traps, spring traps, and mothballs and those fuckers wont leave. I've drove the thing every day for the past 4 months.

I need any spots they could be at or any other way to get them out.

BugBombs from the Hardware\Grocery store might work; they come in 3 or 4 packs, small aeresol cans.
A few years back, had field mice in the 2car garage;
after they chewed thru several plastic garbage cans with secured lids where I stored dog food, & made a nest in my trucks AirFilterBox.
I had enough & set off 4 BugBombs, then did a garage cleaning, found ~10 of the little bas'ards dead; no more issues with mice.
For a vehicle interior, I'd first try just 1 BugBomb with it parked overnight outside, maybe 2 again if that does not get rid of them.
Set off the can on several PaperTowels or a Rag, not on the Seats\Matts\Upholstry, as it can stain those.
Also moved the dog food to a metal can.

I'm worried that I be able to find them after there dead because I put poison in there and only 1 died and it took me 3 weeks to find.
It was a terrible smell and we couldn't find it until I hit a huge bump ( basically a ramp in the road/pavement ) and it fell out of the passenger side dash.
I've cleared nest's in the Driver side Quarter Panel, the roof trim ( were the rear door latches ), in the Air Filter Box, behind the glove box, behind the Instrument Cluster, and in both rear doors (in the insulation/stuffing), and in the hood.

I have this problem every year. Why wife feeds animals. I kill them.

Moth balls work magic
traps work put out five on the passenger floorboard.
poison will cause them to seek water and die in your firewall and air intake (check the air filter)

after they hey get sick of your truck you can stop moth balls

I put moth balls in a couple of months ago and they didn't work so I took them out about a month ago.
I just spent a day fighting the truck for the rear seats and sprayed Rodent Repellent.
I Have tried to take the rear trim panel of and I could get the rear trim separated from the B pillar trim (or the rear side trim).
The rats are nesting in between the rear trim and rear of the cab.

Good old fashioned traps with peanut butter smeared on the trigger/release?

Just feeling bad for you
 

I’m super allergic to rodents so I’d be dead in your shoes.

traps work

you need to check your intake and air filter and interior heating a/c cowl too.

up behind the dash and between bed liner if you have it.

I gave you all the advice I had now just a tip of the hat. Good luck.

I had the same problem, nothing worked even the traps with peanut butter. I ordered Fresh Cab online and it repels them with smells they don't like. You can get it at Tractor Supply and places as such. It comes 4 pouches a box and they say they last 30-90 days, mine are on about30 days and they have not been back in since, they don't even get under the hood hardly too. Give it a shot and see, I'm satisified with mine.