Power-washing doorjambs - a highly debatable method.
IMO, it depends on:
1. Type of vehicle?
2. How much is the customer is paying for the job?
3. How much time is given to you?
4. If you are a detailer, who're your target customers?
If it's an old vehicle with hardly any electronics or a dirty 4x4 and the cheap-skate customer is looking for a super-cheap, "quick and dirty" job...then power washing the jambs could be a convenient, albeit crude and unprofessional method.
On much older cars with little or no electronics thats really dirty, a little power washing won't hurt.
But on modern vehicles with electronic modules, CAN-bus data bus systems, connectors and sensors everywhere, power-washing door jambs and other areas (EXCEPT the exterior paintwork) is a NO NO for me. In many vehicles, its main ECU could be located inside the front kickpanel (eg: many Mitsubishis). If water seeps in, and touches EVEN ONE contact pin...the ECU is fried. I've seen this happen.
Other bad practices seen on the Internet
Spraying/spritzing liquid interior detailing products onto certain areas such as the front cabin's centre console or centre fascia. On Mercs, Beemers and especially Audis, these are often the areas where the "info centre" switches and knobs reside (Eg: Audi's MMI).
I do Audis very regularly as my company services the local Audi dealership.
On Audis, especially the top-end models (Q7, A6, A8), there's lots of buttons on the centre console.
Audi has already alerted their dealers (TSBulletin)that any liquid spilling onto these areas might slowly migrate into the underneath and could damage the control units UNDER the centre console. The warranty will not cover these damages. During a heavy downpour, even water dripping from a wet umbrella, or a few drops of coffee...if it falls onto the MMI switches and through their gaps, could cause problems. CD player wd not operate, AC controls freeze etc etc.
Example: A friend's Audi S8.....his Bang & Olufsen system is no longer working.
In some new VWs, there is a Comfort Control Module that's under the front floor. If sills and other surrounding areas are heavily power-washed, water could seep in through the footstep, flow onto the floor (gravity) and end up damaging the control unit.
Example: a Passat CC with it's horn not working, despite chaging the horn unit. The Comfort Control Unit was damaged by moisture.
Removal of window tint film from front windscreen.
Many Internet videos show spraying of lots of chemicals onto the glass to remove the tint film adhesive residue.
The copious amounts of liquid will flow downwards to the dash, through the demister vents, and drip onto any electronic control module and/or its wiring under the dash. Car won't start (Example: Suzuki Swift 1.6). Vents shd be masked off using water proof tape (eg duct tape) and dash covered with a large towel. That's what I do.
Large MPVs with sliding, "power" side-doors - spraying lots of cleaner onto the big piece of plastic entry footstep panel.
Since it's an electrically-assisted "power sliding door", its motor, control module, and wiring loom may be directly under this plastic foot step (eg: many large Toyota MPVs).
