Hi All

Slight problem.

When i go my 05 Streetwise it had a Pioneer flip front single CD/Radio, a DEH-P3500MP, is this a standard fit unit for this age of car?

Whilst it worked, the CD eject button was dodgy but luckily I had a Pioneer Radio Cassette, a KEH-P6900R and matching CD autochanger, CDX-P25 sitting spare from a previous Rover )HHR) so I thought I’d fit that.

No problems connecting it as all the plugs were the same.

Now it all works but it’s a bit of a pain.

I think because the live feed is only live with the ignition on every time the car is switched off or is restarted (when i stall it, *laughs*) the whole unit starts again.

If I have a CD playing it reverts to the radio and if I change it to CD it goes to CD1 track 1.

So is it just a case of finding an always live power feed and connecting the unit that way or is there a specific way of supplying power so it does not do that?

And any idea how much power such a unit would use as the car does not get that much use and flat batteries are not fun.

Cheers Bean

Pioneer was newer a standard fit for Rovers.

From your description seems to me that you have reversed permanent power and switched power.

Usualy that are yellow and red wires that need to be switched, however I will need to know what wire collours you have on connectors in order to be able to help you further.

Your unit is most probably wired correctly.

The ISO socket in your car has both a +12V feed and a switched 12v feed.

See: https://en.wikipedia.org/wiki/Connector ... ss_Adapter

When you turn your ignition off OR to position 3 (momentary starter motor engage - to start the engine) then the switch live drops to 0 volts.

I can see that you may be tempted to wire the switched live (pin A7 as per the link) to a permanent live (pin A4 as per the link above) which would keep the radio powered at least from position "1" on the ignition switch.

However, the reason the switch live drops to 0 volts during starting is because the starter motor draws so much current from the battery that the 12v battery feed is extremely noisy with lots of low and high frequency noise easily alternating between something less than 10 volts (maybe 7 or 8 volts!) and the full multi-cell voltage of 13.2v. Sensitive electrical equipment such as your car stereo use the switched live dropping to 0 volts to SWITCH OFF during engine cranking, to protect themselves.

If you wire the switched live to a permanent live feed, during starting or restarting, you may literally destroy your head unit. It might be an over-voltage condition (spike) that kills it, or it could be the huge variations in supply voltage whilst cranking that kills it.

Is the Pioneer unit connected directly to the Rover's harness, or does it have something different to ISO block terminals on the rear and are you using an adapter cable?

The only safe situation that could be rectified is if there is an adapter lead in use and it is using the switched live feed on the Rover ISO harness as the permanent live feed line for the Pioneer-specific plug.

Some adapter cables have bullet connectors on the live and switched live leads, and these can be switched around easily.

Thanks for the replies.

The plugs off the back of the original unit plugged directly into the new unit (no adapter) and TBH i, probably wrongly, assumed that as the brands were the same and the plugs were the same that i could just plug it in.

Well i could as it kind of works.

But as you explain the lives are probably in different places on the plugs i'll have to look further at it.

Cheers Bean

Bean66 wrote: ↑Sat Oct 01, 2022 8:36 pm Thanks for the replies.

The plugs off the back of the original unit plugged directly into the new unit (no adapter) and TBH i, probably wrongly, assumed that as the brands were the same and the plugs were the same that i could just plug it in.

Well i could as it kind of works.

But as you explain the lives are probably in different places on the plugs i'll have to look further at it.

Cheers Bean

To swap over easily, you could try this lead: https://www.audioboffins.com/iso-extens ... fullSite=1 or maybe you can find one cheaper elsewhere.

It has bullet connectors halfway along the 12v and switched 12v leads, so you can swap them over. It's a patch/extension lead so one end connects to your Rover harness and the other to the head unit. No need to use the brown connector lead for the loudspeaker connections - just the lead with the black plugs is all you need to add.

Hi All

Thanks for the responses and suggestions.

To me it seems like the internal live wiring on the Pioneer DEH and KEH units is the opposite way round as despite the plugs being the same shape the lives are switched.

After testing it I ended up cutting and reconnecting the wiring and it all now works perfectly, well as good as a 20 odd year old Radio, Cassette, CD autochanger can, which is better than an old Radiomobile 1070X I’ve got does.

Cheers Bean