NARPRO is a local network of outstanding, independent car repair shops in the Valley with reputable and certified mechanics and shop stats. Below is a lot of advice and tips that will be relevant to any Monsoon related issue you could have with your car.
From the NARPRO Family, some info and tips for you:
Bob McLeod from Sunland Auto Service in Mesa was asked how to monsoon proof your car and he said “You have a better chance to Monsoon proof the person than their car.  It’s the way the people drive in inclimate weather around here that are causing their own problems.  They need to slow down especially when driving through standing water to prevent water from coming into the engine bay.  So slow down and take your time.”
When is “Water Too Deep To Drive Through”?
– If the water is less than ½ the height of the vehicles wheels there is little concern.  However always drive slow to prevent water from coming into contact with electrical systems and air intakes.
– If the water level tops ½ of the wheel it would be prudent to have the vehicle inspected by a certified technician.
– Short term exposure is unlikely to have significant impact, but minimally all fluids should be inspected.
If your vehicle stalled after a heavy storm you have options.
1. Find the affected component(s) and remove the moisture.
2. Let time remove the moisture.
3. If you are stalled in deep or under water – Do not try to start it.   Water in the intake or engine it is likely to cause severe damage.  Have the vehicle towed to a NARPRO facility.  Certified technicians can repair the condition and may be able to prevent future recurrence.
Frank Leutz of Desert Car Care in Chandler sells a lot of windshield wipers this time of year and has found that “No matter how good the wiper blade and it’s guarantee, they all seem to last a year.  Everybody seems to wait until they need them and then they don’t work or worse fail completely and permanently scratch the windshield”
McLeod of Sunland Auto also pointed out that with the increased humidity air conditioning systems are working harder to remove the moisture in the cabin and their is a lot more water coming out of the condensation tube underneath vehicles.  “People should not panic when they see a puddle under their car during the monsoons.  The amount of water that their air conditioners are pulling out of the air is probably 10 fold when it’s over 30-40% humidity.”
One other tip McLeod recommends is when parking in the shade beware of trees or shrubs that shed leaves and debris into the exterior fresh air intakes just in front of the windshield.  “Debris can sometimes cause the air conditioning condensation tube to clog and not be able to drain the water which can cause mold and mildew problems, making the inside of the vehicle smell and eventually corrode the condenser which leads to air conditioning failure.”
Tires and brakes are essential any time.  Driving in (technically on) water tests them even more.  Additionally, streets can develop an oily slime layer creating even more demanding conditions especially during the first hour of rain. 
NARPRO recommends a certified technician perform a comprehensive vehicle inspection at least twice a year.  They will alert you to conditions current and pending which will assist you in managing and maintaining your vehicle; reducing both the cost and stress of vehicle ownership.
Here are some other monsoon tips concerning safety involving the readiness of your vehicle:
When a storm approaches…
Find shelter in a building or car. Keep car windows closed and avoid convertibles.
Should a power line fall on your car while you’re in it, don’t touch anything metal in the car, and stay inside until professional help arrives.
Flash Floods Can Take Only a Few Minutes to a Few Hours to Develop…
– A flash flood WATCH means flash flooding is possible in your area.
– A flash flood WARNING means a flash flood is occurring or will occur very soon.
– If driving through a flooded area, DO NOT try to cross washes with water in them.
– If your car stalls in rapidly rising waters, abandon it immediately and climb to higher ground.
– Don’t enter a dust storm if you can avoid it.
– Turn headlights on and slow to a prudent speed.
– If you pull off the road, get as far to the right as possible. Turn off the car and headlights, and set the parking brake. Keep your foot off the brake pedal – other drivers may think you’re a car in motion.
– Rain reduces traction and causes tires to hydroplane. Slow your speed accordingly.
– Water on roads may be deeper than it looks. Watch for vehicles traveling too fast. They can throw up blinding sheets of water.
– Don’t cross rain-swollen washes. You can be caught in a flash flood that can sweep your vehicle and its contents away.
– Pay attention to hazard signs and roadblocks. Ignoring them threatens life and property, and can result in enforcement action by police.
Stuck in a wash:
(Control of a vehicle is lost in 6 inches of water. Most vehicles will begin to float in 2 feet of water.)
1. If you have a phone, call 911.
2. If the water is still low and you can wade to safety, do so, but beware of floating debris. 
3. If the water is too high to wade safely, if you can, climb onto the roof and wait to be rescued.
If you are new to Arizona, be aware that there is a rule called the “Stupid Motorist Law”. If you have to be rescued, you will have to pay for the expenses used to get you out of the problem. Just try to stay off the roads when a storm hits and don’t assume you can drive through water…