CM5908 to a Continental TR7412UB-OR Wiring Help and Premium Sound Questions

[Colt601]

Hi,

I recently purchased a 1991 318is. The car came with a non functioning BMW CM5908 radio (works randomly and when the car is shut off the anti theft portion of the radio will beep until the battery has drained). When I pulled the radio it was obvious that the car did not come with this unit since the wiring connectors were spliced on.

I ordered a Continental TR7412UB-OR which accepts an ISO plug. The CM5908's wiring is very different and was hoping to get some help figuring this out. I purchased an ISO to E30 adapter from Ebay but the E30 part does not work with the CM5908.

Here is the new radio:



And here is the wiring from the old radio:



Any help here would be greatly appreciated.

Secondly the car did not come with premium sound but I would like to install it. However I'm having trouble locating a place to buy the new speakers. I'm also wondering if the head unit will power them or if I will need an amp too?

[ScottSneed]

I would splice the wiring from your e30 harness and fit them to the Continental. Make sure you get the right diagram, check if you have the fader switch. It is pretty straight forward.

As for your question about the premium sound, from my understanding. the rear speakers are pretty much plug and play but you will need to cut your shelf just a bit to fit the premium speakers or get a premium speaker shelf. A good time to redye it as well!

The front speakers are pretty much plug and play as well, but you will need to plug in a third wire which is hidden behind the harness in the corner. You can splice it and attach it to the premium speakers or get creative. The tweeters have hidden wires behind the plastic panel as well you plug in and itll work if you did the front speakers correctly.

So in all, rear speakers are plug and play, you will have to trim your shelf for it to fit or get a premium shelf.

front speakers, you will need to connect the 'third' wire.

tweeters, wires are behind the cover tucked in.

The speakers are available new still but are costly, I would fetch a used set on here or ebay.

[Colt601]

I would splice the wiring from your e30 harness and fit them to the Continental. Make sure you get the right diagram, check if you have the fader switch. It is pretty straight forward.

As for your question about the premium sound, from my understanding. the rear speakers are pretty much plug and play but you will need to cut your shelf just a bit to fit the premium speakers or get a premium speaker shelf. A good time to redye it as well!

The front speakers are pretty much plug and play as well, but you will need to plug in a third wire which is hidden behind the harness in the corner. You can splice it and attach it to the premium speakers or get creative. The tweeters have hidden wires behind the plastic panel as well you plug in and itll work if you did the front speakers correctly.

So in all, rear speakers are plug and play, you will have to trim your shelf for it to fit or get a premium shelf.

front speakers, you will need to connect the 'third' wire.

tweeters, wires are behind the cover tucked in.

The speakers are available new still but are costly, I would fetch a used set on here or ebay.

Will I need to run an amp or can the head unit power them?

[othatseric]

I really recommend getting the universal ISO harness for the conversion, i used one for my continental and made things alot easier to cut/strip the universal harness and the old radio harness and crimp on new connectors. If you go the same route heres a quick guide:

Car Harness: -> ISO Harness continental:
Green/red -> Yellow(constant 12v)
Grey/red -> Orange(illumination)
violet/white -> Red(ign. 12v)
Brown -> Black(ground)

Blue/red -> grey(FR+)
Blue/brown -> grey/black(FR-)

Yellow/brown -> green/black(RL-)
yellow/black -> green(RL+)

blue/brown -> violet/black(RR-)
blue/black -> violet(RR+)

yellow/red -> white(FL+)
yellow/grey -> white/black(FL-)