Push a few tasty pet treats into the vent. Find a small , hungry monkey to fish them out. The phone is sure to follow.
Three Things… A Shop Vac, Duct Tape & Poster board. Use teh shop vac with a flat type of nozzel that alloqws you to get into cracks and crevases…? and then cut the poster board to fit just around the flat end of the nozzel that actually extends the the flat portion and place into the vent…tape the poster board around the flat end of course. turn that puppy on andsuck it out!
Try fast-curing epoxy at the end of a coat hanger. Push down the hanger until it touches the phone, hold for a few minutes until the epoxy cures, then pull. It may damage the phone but it shouldn’t be a problem since you appear to be more concerned about removing the phone than reusing the phone.
You’ll need a length of something like electrician’s fish tape (or some other springy flexible metal tape). The recoil starter return spring from an old Briggs & Stratton could be straightened to do this job. Also needed is some ribbon (about an inch wide), superglue, and a cotton ball.
Affix about 10 inches of ribbon to the end of the fish tape. At 11 inches from the same end of the fish tape, glue the cotton ball onto it. The cotton ball should be about an inch away from the loose end of the ribbon. You’ll be best to re-arrange the shape of the cotton to fit around the fish tape. Now turn on the A/C. Gently insert the fish tape until it has snaked past the phone. When the fish tape has passed on one side of the phone and has reached the right spot, the cotton ball will obstruct the flow of air around that side, causing the ribbon to seek the other side once it passes the far edge of the phone. Listen carefully for the ribbon to begin flapping when the loose end has shifted to the other side of the phone. Now slowly pull the tape back, allowing the ribbon to blow down the opposite side of the phone as the fish tape. When the end of the ribbon comes into view, pull both it and the fish tape. The phone will be stuck between the two and should pull out of the duct.
I bought a fiber optic camara for just such a car project. It worked great, and now I can do low- budget medical procedures. It has a 6 ft. scope that you can aim and watch while you poke around with a coat hanger, etc.
using a laptop or netbook, attach a small webcamera to a slim handheld tripod. He can thread it into the duct to see if the phone is lodged in an awkward position, then thread one of the above suggestions to retrieve it. (also using the webcam)
I have a 2002 M3. I was carrying a box of .410 shotgun shells in the back floorboard and box broke open and one shell when into the driver’s side underseat heating vent, exactly as Pradeep described. I did the steep hill maneuver, no luck. I am an aerospace engineer, working at an Air Force Base, where bringing explosives onto the Base is forbidden and illegal, even ones irretrievable in the vent system of the vehicle transporting the explosive. So I got a jet engine borescope and a magnetic telescoping “parts retriever.” Oh, but you say, “it’s a shotgun shell, made of brass and lead.” Well, I experimented with one of the 24 remaining shells and the primer is made of some sort of magnetic material. So, armed with the borescope and the magnetic retriever, I was able to find the primer end of the shell and gently grabbed it with the magnetic tool and removed the loaded shotgun round. Good luck Pradeep, I hope something on your phone is magnetic. Robin 2002 BMW M3 & 2004 MB CL55AMG.
The removal process is quite easy and propulsive. Here in central Kansas because of the very dry conditions, the 4th of July Holiday was postponed until wetter weather arrives. This has caused a surplus supply of unused fireworks stored in ever garage of anxious pyromaniacs locally. My idea would be to use a particular aerial firework known as a Thunderhead. No pretty colors, no awesome display, just a loud thunderous sonic boom in the heavens followed by the crashing of your neighbors house glass.
So the first step to this process is to locate the duct outlet where you think the cell phone is lodged. Second is to remove the register at that outlet. Third step is to duct tape the artillery launch tube, with the projectile already loaded into the tube, to the suspected duct outlet. Fourth step in honor of the forth, is to light the fuse and step back. Once the process is started, the first minor explosion will be the launch powder propelling the projectile into the duct and hopefully up to the lodged cell phone. The second more major sounding explosion will be the Thinderhead propelling the cell phone out of the ductwork and into whatever happens to be in it’s direct path of exit. . . Now with your cell phone in hand you can go to your provider and explain that it was not water damage that disabled your phone, and that you’d like a new or like new replacement. Preferably one that has not been the victim of a fireworks related accident.
Let the batteery run down and forget all about it. 
Going to the dealer to see the in-stock part is not a bad start, but I have solved this
general type of problem by going to the self-service dismantler or pick-your-part.
Sometimes you can find a car of the correct type already partially disassembled.
It is the mechanic’s equivalent of the physician’s illustrated anatomy.
A strong vacume with a narrow mouth. Duh.
Absolutely love the show. You guys are hilarious!
To dislodge Pradeep’s cell phone:
Use a vacuum. Those vacuums at the self-serve car washes are particularly powerful. You should strongly consider attaching a garden hose to the vacuum hose in order to get inside the narrow opening. Use a hose that has thick walls - otherwise it could possibly collapse from the vacuum effect. Cut off a 2-3 ft section and also cut off the metal end. I would consider a clean cut/no rough edges - and at a 30-45 degree angle. Use an adapter to accommodate for the difference in diameter between the vacuum hose and the garden hose. You may have an adapter - or you can buy these separately at Lowes/Home Depot. Use duct tape to get extra air-tight seal. You possibly may want to smear a bit of grease on the very end of the hose, so that when it makes contact with the phone it will also be air-tight.
Good Luck!
Jack Brown
I agree with Frumenty – just go down to your local tool rental shop and rent a fiber optic borescope. You can use that to see how the cell phone is lodged in the vent, and then watch what the end of the grabber is doing as you snake it up the vent to try to snag the phone.
Get a vacuum with a good suction, attach a crevice tool and stick it in the opening. You may also find other items that have mysteriously disappeared.
I spent many years as a L&D nurse…
Go to the car wash. The kind with the do-it-yourself really powerful vacuum with the long narrow nozzle and
since the car can’t push, suck that baby out!
I think it could be done for less than $1. Go to a car wash with a powerful vacuum and suck it out of the vent.
I’d just leave it and get a new phone. The battery will die eventually. Had the same problem in our house. My son dropped his cell phone down the heating vent. We could hear it in the distribution box in the garage – it lasted about a week, then was quiet. As far as I know, it’s still there.
A small set of Metric wrenches is about $20.00. He may need a metric screwdriver to loosen the trim on the carpet. He’ll gain a great sense of accomplishment and save a bundle. And, he may be able to resell his metric screwdriver to Ripley’s.
Has he tried mirror(s)?
Few years ago our clothes drier began stinking to high heaven!!
It was so awful that we figured it had to be something like a dead animal!!
Called repair guy. He came out, unhooked the gas, pulled out the drier, fiddled around a bit. Gave up and said: “It’s shot. You’re going to have to replace it,” as he hooked it back up.
Right after he left (was super glad I’d watched him, since I’m a klutz of a mechanic or repair person) I unhooked the gas, moved it out and (with my wife’s more-or-less encouragement) began poking around. We got a mirror and flashlight and eventually we saw a dead red squirrel (who must have come in through the drier vent in the wall of our house) and were able to pull it out.
After several weeks and several treatments of strong spray, it quit smelling, and it’s worked fine for several years!!
Try a mirror or two.
I believe this image should help. It is what the duct looks like without carpeting.
Not sure how far up there it is, but it might be better to go at it from the other end, if you know what I mean, just get up under the dash.
Hope the pictures are helpful.