Changed head unit - No power?

[blagger89]

Afternoon all,

Just been given a W reg 1.7 Puma by my uncle as he no longer needs it.

He had a third party cheap head unit installed and I wanted to replace it with one I've had in all my cars as it has iPod functionality.

Pulled out the old one, disconnected the connecting blocks and swapped in the new one, plugs all connect, so its literally like for like. However, this new one won't power on apart from if the CD eject button is pressed, and then immediately turns on.

The only real difference on the back of each head unit is each has a different fuse installed, and thats pretty much it.

I will be putting pictures up if its easier but can't figure out why it won't work. I've had this radio in my Focus, Fiesta and Corsa and it's always been a straight swap with no issues!

Any help would be great.

 

[Robyorks]

Hi Blagger89.

Welcome to Puma ownership

 

[blagger89]

Cheers

Heres some pictures of both HU and the wiring in the Puma.

This is the new unit with the connectors straight from disconnecting in the Corsa.

This is the exicsting HU with wiring.

Wires available in the Puma.


They all connect together so I can't figure out why the new unit won't power up.
Just realised I've posted this in the wrong subsection - was meant to be in ICE. My bad.

 

[Wild E. Coyote]

When I bought my Alpine, I had to swap the two wires at the back for the power. Granted, it was brand new HU never installed before, but still… Perhaps have a look at that posibility as wel?

 

[PhilLew]

I've seen some head units that will power up when you press the eject so you can remove a cd without having to switch on the ignition, could be that you have a permanent live but no ignition live. Did the unit that came with the car turn on and off with the ignition alright?

 

[blagger89]

The existing Panasonic unit only turns on when Keys turned to Ignition I or II.

The other unit when put in doesn't turn on at all but if I put it back in the Corsa it starts up as expected. I'm tempted to pull the wires out of the ISO connectors and try get a wiring diagram to just find which is a power one then solder them together and then go from there. On the Panasonic the yellow cable is labelled Battery and I have my JVC manual in the attic somewhere so that'll be a job for tomorrow.

 

[PhilLew]

Does the old Panasonic unit remember the tuned stations after it's been swithced off or due you have to re-tune it each time?

 

[blagger89]

The Panasonic HU works perfectly fine, remembers stations, bas and volume settings, where the CD was last played.

I'm sure I don't need one of the ISO adapter kits as it already has a 3rd party HU in and they all connect up. I'm at work and it's dead atm so I'm going to have a fiddle around with some of the cables and see what happens.

 

[blagger89]

Got it sorted, noticed on the car side connector that one of the wires on the power block was in a different position to the JVC side, it was a cable marked "accessory" so pulled it out and put it in the right place and voila. Worked. Happy freaking days!

 

[PhilLew]

:grin: :grin: :grin: :grin: :grin: :grin: