OE Radio help.

[bob12]

Originally Posted by swedish brick

Just been out to the car and made a discovery! Not a particularly useful one but...
My car only has front speakers? ..................

The wiring colours on the radio multi plug are:

1 - red + white
2 - grey + red
3 - black
4 - black
5 - unused
6 - yellow + white
7 - unused
8 - blue
9 - green
10 - black (larger diameter wire)
11 - yellow + black
12 - red
13 - unused
14 - unused

Partial up-date - the above wiring colours and multi-plug pin-outs are the same as the CR-702 that came as original equipment with my 1990 745 (albeit with speakers all round and an amp).

Unfortunately, short of removing the radio now fitted to my car I do not appear to have a record of the loom multi-plug colours but, I suspect it is different from yours as it has a later loom for LH2.4 that carried over to the first few years of 940's.

I recall I gave up trying to work it out when I discovered that those 'good people at Audoleads' had worked it all out for me by producing a truly plug and play wiring conversion adapter set. That meant that all I had to do to upgrade to a modern ISO head unit wiring and by-pass the amp was to buy one for about £10!

Bob

[swedish brick]

Originally Posted by bob12

Partial up-date - the above wiring colours and multi-plug pin-outs are the same as the CR-702 that came as original equipment with my 1990 745 (albeit with speakers all round and an amp).

Unfortunately, short of removing the radio now fitted to my car I do not appear to have a record of the loom multi-plug colours but, I suspect it is different from yours as it has a later loom for LH2.4 that carried over to the first few years of 940's.

I recall I gave up trying to work it out when I discovered that those 'good people at Audoleads' had worked it all out for me by producing a truly plug and play wiring conversion adapter set. That meant that all I had to do to upgrade to a modern ISO head unit wiring and by-pass the amp was to buy one for about £10!

Bob

Thanks Bob!

I’m not good with auto electrics and I’m definitely not knowledgeable with ICE either, so from what your saying I assume it means the head unit I’ve got is not original to my car?

If it’s not original it was probably put into my car because the original one died. Because it’s not the original it won’t work because my car doesn’t have the amp, leads and speakers etc it needs?

...and therefore it’s going to now be very difficult to find a head unit that will work with my cars equipment? Or, for me to find working 30 odd year old bits to put in to make the head unit I’ve got work?

Basically it’s a bit of a lost cause!?

Sorry if I need it all spelling out! I think trying to stick with OE is a lost cause then?

Last question (I promise!), what is going to be my best option now for a working radio? One of the modern units posted on the previous page?

Cheers for the help so far guys!

[lnparry]

Hi,

I've come to this post late but I am pretty sure my 1988 740 had a separate amplifier on the original Volvo cassette / radio but it was mounted under the dash on the passenger side so if you are still struggling to find the amp it may be worth looking there.

Cheers,
LeeP

[bob12]

Forgot to add that the oem of the CR-702 was Alpine. I have some of their colour codes and some are the same but, not others!!

Also, I have a mass of other wiring info allegedly for these HU's but, none quite tie-up with Volvo's amazing go-it-alone attitude of the era.

When you think about it it must be quite simple!! The HU must have a + feed and - . There must be an out to feed the electric aerial. On top of that, originally the dash dimmer worked the HU display. More importantly there will be left and right speaker + output wires - . The question is did they use separate neg - for the speakers or double up on them.

If I find anything else I will post.

Bob

[swedish brick]

Someone else suggested I try putting a cassette in the HU and see what happens?

Is that worth a go, or is it more or less a dead certainty that it’ll be a pointless waste of time? I don’t really want to get any cassettes stuck in it or torn up!

I mean, it’s turning on but doing nothing else so presumably it won’t matter if the sound is from a radio station or a cassette, it won’t work either way?

[Laird Scooby]

Originally Posted by bob12

When you think about it it must be quite simple!! The HU must have a + feed and - . There must be an out to feed the electric aerial. On top of that, originally the dash dimmer worked the HU display. More importantly there will be left and right speaker + output wires - . The question is did they use separate neg - for the speakers or double up on them.

If I find anything else I will post.

Bob

Also a permanent +ve feed for the memory and speakers should have two leads each, neither of which go to -ve as this can damage the output stages of either the amp or the radio.

It is simple enough though and most modern units don't need a separate feed from the lighting circuit. Those that do only use it to arbitrarily dim the display to a "night" setting.
Because the default setting for Volvo lighting brings the sidelights on with the ignition, this is usually best left disconnected.

[bob12]

Originally Posted by swedish brick

Someone else suggested I try putting a cassette in the HU and see what happens?

Is that worth a go, or is it more or less a dead certainty that it’ll be a pointless waste of time? I don’t really want to get any cassettes stuck in it or torn up!

I mean, it’s turning on but doing nothing else so presumably it won’t matter if the sound is from a radio station or a cassette, it won’t work either way?

You could give it a go but, if there's no sound as you suggest I doubt that using a tape would make it work.

If a tape gets jammed it's easy to remove it by unscrewing the top cover of the HU and releasing it .... another reason I dumped my antique CR-702 for a far more sophisticated all singing and dancing HU set-up that also kept me within the bounds of current law regarding mobile use while driving! Bob

[bob12]

Originally Posted by Laird Scooby

Also a permanent +ve feed for the memory and speakers should have two leads each, neither of which go to -ve as this can damage the output stages of either the amp or the radio.

It is simple enough though and most modern units don't need a separate feed from the lighting circuit. Those that do only use it to arbitrarily dim the display to a "night" setting.
Because the default setting for Volvo lighting brings the sidelights on with the ignition, this is usually best left disconnected.

.... just so much to think of Dave .... thank goodness for Autoleads.

[swedish brick]

What would you guys do in my position?

The only reason I want an OE radio is to keep the dash looking right.
It’s looking increasingly likely that I’m not going to get any of the original stuff to work again though...

Can it be made to work again easily?

Or

Should I accept it’s all knackered and live without a working radio or get one of those modern HU’s off eBay that will work?

[Laird Scooby]

The previous owner of mine had mutilated the wiring for mine so i had to rewire it and solder new ISO plugs into the loom.

That got rid of the Sendai CD789 radio/CD head unit (£20 brand new from places like Hellfrauds and Maplins) and meant i could add this and the CD autochanger :



Does the job nicely for me and i've added a BlueTooth FM transmitter/handsfree jobby so i can have the music from my phone playing through the stereo while using the navigation function/sat-nag and if a call comes in, it mutes the music and sat-nag and gives me full duplex handsfree capability,