Treat it as a cd player -
Whether its CD or DVD the principles are the same
A laser pickup shines a laser light of (Tekky alert
) a fixed wavelength at the pits and troughs in the disk
CD's use one wave length, DVD use another And Blueray uses a different laser and wavelength altogether
CD/ DVD / Blue ray burners have 2 way (CD DVD) pickup head & a blue ray laser head in the transport mechanism of the unit
Dual layer discs have 2 layers of writeable media this cant be read or burnt in one of two ways
Altering the focus of the beam so it focuses on the upper or lower layer as required, or moving the laser head closer too the disc -
thus altering the focus position.
Right now the boring stuff is out of the way ...
Either your disk is fubarred or your unit - at this stage we dont know which
Going with the cheaper fix - Drive to your local dealer nad ask if he can pop in a new disc -
If it reads chances are its the disk
If it dosent, then its the unit .. get a quote and leave
Option 2 tekky time
If you can get the unit out of the car, and open it up LEAVE THE POWER OFF
As i said, for all intents and puposes its just a glorified CD rom drive - open the unit up and remove the top cover from the CD housing
Inside you will see the CD pickup in a slot, it may be straight , or have a slighty curved apature , but essentially its two rails with a pick up assy
the moves along it ..
by hand, move the pickup assy along the rails
A) To see if it hasnt jammed ( the grease dries out and they can stick)
B) To force it to return to its home postion
WARNING WARNING WARNING
Power the unit up - see if the pickup does a round trip back and forth - if it does the transport side would appear to be working (good)
WARNING DO NOT LOOK DIRECTLY INTO THE LENS OF THE LASER PICKUP - LASER LIGHT CAN BLIND
Repeat the operation, but this time look at the lens in the top of the pick up unit it should jump up and down a couple of times
This is the focus self check if the lens jumps its helpfull
You may see a faint red light or flash as the lens cycles (this is the actual laser) if you dont see a light normally thats not a good sign
Get some isopropanol - and dampen a cotton bud, wipe the lens with the cotten bud to remove any grime that may have accumulated, and also
it may remove any shit that could be clogging the focus array
If the unit dosent do any thingwhen you power it up, it may be beacuse it dosent see a disk inserted - get an old cd or dvd and insert it to see
where the trip switch is to fool the unit there's a cd / dvd in the unit
if all the above works, put the lid back on and try your nav dvd's if non of them work, then the laser pickup is prolly borked -
Then go hunting for a pickup ass on ebay
https://www.ebay.co.uk/itm/NEW-OPTI...499557?hash=item54627b48a5:g:wX0AAOSwLVZVimBC
gives you an idea of what your looking for
nb thiats just a generi pickup - its not your one