I bought my truck a year ago from a local dealer. It had 18,000 miles on it at the time. When I test drove it, there were a few air fresheners scattered throughout the cab. After their scent subsided, I discovered why the dealer put them there. Quite often, when I begin a short trip, I (and my wife) detect a strong odor in the cab, usually after I make a turn. The smell is similar to feline urine. Eventually the odor dissipates. My first response was to change the cabin filter, which did not resolve the issue. I notice that my a/c drain drips best when the truck is parked with its left side downhill. A relative suggested my a/c drain line was clogged, so I had that checked by the dealer I bought it from and was told it was clear. I live in SW FL so humidity levels require the running of the a/c almost continually. Any insight from the experts?
I would suspect a leaking heater core.
if water is leaking in some where and the rug gets wet and starts to deteriorate it will give off a the same smell or like food has been left in the vehicle and has gone bad smell.
Mix up a few gallons of warm water and a product called Odo Ban. Park the truck outside. Pour the mixture along the base of the windsheild… all of it. Let is sit overnight and rinse in the morning. Repeat if it isn’t all gone after the first treatment.
Full disclosure… I live in Florida, I have had this problem.
just curious, will that hurt the paint if it gets on it?
The pee pee? Or the Odo Ban? The Odo Ban won’t hurt anything but I don’t let it splash much on the paint. The pee pee I can’t really control… cats you know! 
It’s probably mouse pee if it is in fact pee. This might be in the vents, heater core or dashboard. Or it could be mildew from water leaking also.
I had some luck with ozium spray. I spray it on the carpets. just try not to breath it in when spraying and let sit for a few hours or over night. then open the doors and let the car air out for a few minutes. you can get it at the autoparts store or online.
Ozium, or Ozium Glycolized Air Sanitizer, is a spray for improving odors and reducing airborne bacteria within a closed area. The spray is intended for use in public buildings, hotels, hospitals and schools. The manufacturer claims that Ozium contains “active ingredients that actually cleanse the air.” Once sprayed within a confined space, its lighter-than-air particles linger for up to three or four hours. As opposed to most “sanitizers” or room fragrances, Ozium does not cover up odors, but eliminates them.
I’ve used Odo Ban. It’s very effective. There’s also white vinegar. If you do a 50\50 mix with water and spray it at the source it neutralizes the smell. You will smell the vinegar for a short while, but it will dissipate along with the smell. If it were me I’d try the Odo Ban method first. Sounds like the most effective method. Odo Ban has a smell, but it’s more of a fragrance or freshener smell and it also goes away.
+1
For decades, Ozium was the go-to deodorizer for embalming rooms where odors can be overwhelming at times.
And, don’t ask me how I know this, but it is very effective for removing the lingering odor of marijuana smoke.
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A leaking heater core doesn’t smell like urine, imo
I agree with you . . . I’ve worked on plenty of trucks where the critters build a nest in the hvac plenum. Pretty disgusting smell. And I know what it smells like, because I’ve had to clean out a few nests 
Brake fluid has a similar smell. I would go to the mechanic and ask him to check for leaks.
huh . . .
I’ve been around DOT3 plenty of times, and I never thought it smelled like urine
But opinions will vary 
Agree with @db4690
We have 2 cats, both males. I am very familiar with the smell of cat pee as well as various grades of brake fluid. None of that brake fluid smells like cat pee.