Have a 2002 Camry which has developed a chronic leak in the rain. Water collects mostly beneath front passenger seat, although front mat feels damp. Recent efforts by a body shop to find the leak were unsuccessful. They did report the car was apparently significantly damaged on the passenger front side before we bought it (4 years ago, at an auction; leak began about 1 year ago, initially thought had left windows cracked or something) and were critical of the quality of those repairs. They claimed to have done both water and smoke tests in their failed attempts to locate the leak (after re-aligning the fr. door and repairing rust coming from within the rocker panel - so they have had some of the car apart.) Any suggestions on the leak source?
Do you know if they checked the cowl drains underneath of the windshield? Different car, but I once had clogged drains, and overflow ended up entering the cowl and running down into my air circulation fan - gunked up all of the connections and dripped on the passenger’s side floor.
(The cowl is the big plastic thing at the bottom of the windshield and is where fresh air enters the car. Pop the hood and inspect it looking for something that looks like it is supposed to drain water).
There are four common leak sources for what you have described.
The windscreen would be first to suspect in this case due to the history you provided, and I would not totally rule it out yet.
If you have a sun roof, that would certainly be high on my list of suspects. A blocked drain (maybe do to the accident or repairs) could be the problem. This should be checked. There are generally four drains (one in each corner) for the sun roof. You can pour water into each one to make sure it is exiting under the car and not in the car.
Third is the A/C, this one will show up when you are using the defog or defrost or the A/C. It is also a clogged drain, just a different drain. In most situations you will get water draining under the car with the A/C on.
Fourth would be the cabin air intake. That is the vents in front of the windscreen. If there are leaves etc. that got into that intake, they can block their drain.
With a sponge or a dish soap bottle (not with dish soap) You squirt soapy water onto the edges of the windshield and all related mouldings. You do this while the AC fan is on top speed or without AC on, the air pressure is what you want. If there is an opening, the suds will make you laugh when a lot of bubbling starts. This may not help you find some leaks but it’s worth a shot.