1994 940 Radio Replacement, Missing Amplifier??
 

Hi,

Spare few hours today, so first think this morning I embarked on planned swop over of old CR905 head unit that crackled every time the volume knob was touched to a new Blaupunkt head unit.

Having read up over recent weeks on various threads on the forum about this process, and seemed to be a 'simple, swop of head unit using an amplifier bypass harness, I'm happy with just the 4 door speakers, so realise I will lose the dash speakers.

Anyway, got old head unit out, pulled the drivers side panel that's above your shins, along with the lower kick panel, removed glovebox to run the new DAB aerial to screen.

Can't for the life of me see anywhere the separate amplifier, apparently it's supposed to be silver/black around 6" or so, any pointers on location would be very welcome.

Looked on google images for location of the 940 amplifier but all the photos that show it, do not match up to what I'm seeing on mine.

Another problem is that the bypass harness I have, seems to have a connector that differs from those at the back of the radio??

Many thanks,
Steve

Post 1994 cars don't have the seperate amplifier and use a different harness adaptor.
You will need the Autoleads PC2-19-4.

Hi Gavin,
Thanks so much for the information on this, might certainly explain why I couldn’t find an amplifier.
My car was first registered Aug’94 so assume probably built early ‘94, hence why I was working on basis it had the amplifier.
Found the suggested Autoleads harness on eBay, but will compare the photos to the connectors behind the old radio tomorrow once daylight returns.
Wiring diagram in Haynes has amp showing, can’t really see details, must be getting old, so I’ll have to use iPad to photo diagram so that I can increase size. Assume if no amp, then on connector has all power etc, and the other has speaker cables?? Would they have same wire colours as if there was an amplifier???
Cheers
Steve

Stumped!!
 

Right, daylight now, so back onto trying to sort new radio.

Pulled out old unit again, as having no joy yesterday had just put back loosely in the car.

Part of this needed putting security code in, so previous owner had noted this in handbook. Then noticed the radio technical specs were listed at the back of the guide, states radio has internal 4 x 15x amplifier for door speakers, dash speakers connected with internal filter to front door speakers.

This obviously supports Gavins advice that my model does not have the external amplifier that I had spent yesterday trying to locate......

Looking at the suggested Autoleads harness online, it looks exactly like the one I had bought in readiness to do the radio upgrade on the misunderstanding mine had the external amplifier. All the other harness adapters I've found all mention about bypassing the amp.

Reverted back to old school pen and paper to just note on a diagram of the connectors, all the wire colours on the two connectors from the harness at the rear of space for the radio. Was hoping I could use wiring diagram from Haynes to decipher what cable does what.

Really stumped now, as whilst some of the wire colours match to the Haynes manual, a lot don't!! The only one I have been able to verify is the constant 12v pink/black using multimeter, also assume the two Blacks would be ground??

Enclosed is image of the two connectors that I am trying connect to ISO to Blaupunkt head unit. One is 10 pin (only 8 pins used) and the other is 14 pin (13 pins used)

If I could source matching female connectors, and identify exactly what cable is what, then I could wire up the supplied ISO connectors. Can't seem to find any sources of connectors online that look like what I need, I don't know if they have a technical name, just searching 10 / 14 pin connectors etc.

Any ideas or pointers would be most welcome.

The one Gavin recommended should be right for your car. If the one you bought is the same (and doesn't just "look" the same) and has the same part number then you should be able to plug'n'play.

Don't try and decipher the wiring using Haynes, their diagrams are a nightmare at the best of times! Try this instead, starts on Pg55 by document reader page number :

http://www.myvolvolibrary.info/Tech_...ction-3-39.pdf

There's about 4 different variations depending on 4 or 5 door and other things, make sure you get the right one for your car!

Hi Dave,
Thanks so much for your input, apologies but I just can’t get my head around this, first sign of aging or I’m just dim😀
Adapter I actually have was from Dynamic Sounds, CT51-VL01, photo enclosed, apologies I haven’t worked out how to get larger photos on here yet. Hopefully you can see it has 2 ISO blocks to go to back of head unit, and 2 x 14 pin blocks with an offset side to each connector.

The harness Gavin suggested, Autoleads PC2-19-4 I’ve enclosed photo found online, but looks exactly like the one sitting on my table, with the 2 x 14 pin connectors??

The connectors on my harness from the car hopefully you can see earlier in this thread, are 1 x 10 pin and 1 x 14 pin, although the 14 pin is completely different shape to the Autoleads harness.

I have found on the USA site Crutchfield a harness that does ‘look’to fit, but I can’t see any UK based suppliers??

Cheers
Steve

Dynamic Sounds is the seller and a UK supplier, Crutchfield isn't a brand i've ever seen in the UK but could well be another brand of Connects/Autoleads, the brand of patch lead you have is "Connects2" which means if it looks the same as the Autoleads patch lead, it IS the same as Connects2 have bought/merged/been bought by/other option with Autoleads. I found this out recently while sorting the Steering Wheel Control (SWC) in my Rover to operate an aftermarket head unit (JVC) and needing an interface which just happened to be an Autoleads device. Just for fun there wasn't enough information in the Autoleads blurb about it to indicate whether analogue and digital 0V/earth were linked, what resistance levels it was looking for (the SWC are resistive on the Rover) and a few other things so i phoned the Autoleads helpline and was amazed for the phone to be answered by Connects2. The guy in the tech dept explained the "merger" and how they were the only tech dept left and as such were picking up the pieces from Autoleads. Sadly not much help with my initial query but he did give me a few pointers so i was able to work through and make educated guesses and get it working.

Anyway, back to your problem! Literally plugging the patch leads into the OE Volvo harness then into the head unit should work. You will either have a 4 or 6 speaker system, a speaker each in the front doors, rear doors for a 4 speaker and each end of the dashboard under the grilles on the top of the dash for the 6 speaker system. It shouldn't make a lot of difference in reality.

I would say plug it all in and try it, you should be pleasantly surprised.

The constantly changing electrical systems Volvo used and the bascence of reliable wiring diagrams does make things a bit of a gamble but if you can ascertain the only wires with power on with the accessories (position 1 on the key) switched on are the red (switched +12V) and orange (permanent +12V for the memory) in the DIN-ISO connectors and that the black wire in the power DIN connector does indeed give a 0V/earth at all times then you won't have much else to worry about.

There may be another (purple from memory but might be wrong) in the power DIN that is only live with the lights on, should also be a blue one that is fed from the head unit to tell the electric aerial to raise/lower (+12V/off respectively) which is switched by the head unit itself.

Once again Dave, I’m in awe of your detailed knowledge, very very much appreciated.

The more I’ve looked into this, and as you say, with Volvo changing specs so often doesn’t help, feels like I’ve gone down a proverbial rabbit hole😀

Interesting the companies are now one and the same, progress eh….

I shall take your advice, and after further chin scratching, think I’ve formulated a plan. First off with multimeter in hand I can hopefully identify from the cars harness, permanent live, switched live using key to test, illumination ?? Hopefully a harness pin will give some volts when switching on lights, although mine has daylight running lights? Don’t think it will make much difference???

I have normal aerial in back side window, body colour plug in top of D pillar blanking for a power aerial , I have 4 new door speakers behind factory grilles, and was going to leave the dash tweeters not connected.

However, in the owners manual I found today the dash speakers are wired to the front door speakers, if they work then that’s fine, if not, then I wasn’t expecting to use them, so no biggie.

Just then need to verify the speaker locations in the harness, a couple of sites have given a seemingly standardised speaker location colour codes, looks a good starting point but ideally I want to verify before I plug it all back into the dash.

Is it safe, i.e. not blow my nice new speakers, to do a normal home hi fi battery ‘pop’ test by connecting a 1.5v or 9v battery to each speaker cable in the harness?? This should give corresponding pop from the speaker connected to each pair of wires.

Alternative I suppose is rigging up some sort of test lamp, or can I use multimeter to verify that the cables I think are FR are actually FR, bit of a distance to reach rear door speaker connectors.

Head unit supplied with 2 ISO plugs all nicely labelled, one for power etc and other for speakers, these have no terminals or anything, just ready for crimping etc. Ideally I would like to get just the required 10 and 14 pin connector blocks that will fit directly into the harness, with a bag of terminals so I can crimp and solder terminals and then insert into the connectors to give correct pin connections.

Anyone know where or if I can source bare 10 and 14 pin female connecting blocks that will plug directly into the car harness? Or even what these blocks in the photo enclosed are called ?? Then I can put terminal pins on the ends of my supplied ISO leads, then push the wired pins into the bare blocks, essentially building my own harness to plug directly into these in the car.

Cheers
Steve

At the risk of sounding critical Steve - you're over-thinking this. I am saying this because i was guilty of doing the same but didn't have an option with my 760 as the pervious owner had butchered the original wiring so i didn't have the plugs to plug an Autoleads patch lead in.

Like i said further up, as long as in key position 1 (accessories, NO ignition) the only +12V you have is on the red and orange wires, you're good to go. The illumination input may not even be connected in your head unit, the speaker outputs are standard (International Standards Organisation, Deutsche Industrie Nummer = ISO-DIN) with the exception of some GM and VAG cars (also some but not all Mercs) where the red and orange are swapped to prevent owners retro fitting replacement head units that are non manufacturer branded.

You will likely only get a feed on the illumination with the sidelights and ignition on, normally it's not connected to the DRL circuit which all Volvos had since the early 70s.

The head unit will have speaker protection built in, i wouldn't advise using a PP3 battery and certainly not +12V from the car battery to check for a "click" from the speakers as you could easily burn out the voice coils.

I would plug in your Connects2 patch lead and see what you've got. If you want, check you have +12V on the orange wire without turning the key, check the red wire gains +12V when turned to position 1 on the key (accessories) then switch the key off and plug your head unit in including speakers connection then test. Should be good to go. :thumbs_up:

Hi Dave,

Many thanks, and I really feel guilty in not getting what you’re meaning, it’s really difficult to try to explain, but will try to summarise the issue I have.

Will take on board your points about not using battery, very valid and glad I asked.

You mention using the harness kit from Connects 2 to connect up, my key problem is that it has the 2 ISO blocks for head unit, that’s fine.

The other 2 connector blocks on the harness are identical 14 pin blocks, albeit not all pins used, these simply don’t fit the connectors in the car at all, I’ve tried to re photograph below. They have a step on the side of each block whereas the car doesn’t????

Hope that clarifies what I’m trying to struggle with