wiring help

[tick]

i was taking out the audio leads system for my car, changed round the red and yellow wires at HU iso reconnected the system and now there seems to be no power going to the HU at all. Fuses are ok, can anyone offer some help please

 

[tick]

putting the red and yellow wires through a mutli metre im getting a reading of about 24 v so looks like the prob must lie within the head unit, that sound right?

 

[Dink]

um you should get 0v if you put the meter across red and yellow

 

[stig247]

24v you sure thats right

 

[tick]

connecting the two leads through twosleads of the mulitmetre with the power on was giving me a readin of about 24 volts, that worng?

 

[Dink]

oh yeah thats well wrong as they are getting there 12v from the same source(batt/alt) so should give a reading of 0v(no p.d)

 

[tick]

so what would be the cause of it?

 

[Dink]

now that i can't tell you lol

 

[tick]

so with the engine on,m what would be the voltage passing through the red and yellow to the head unit? must have to be something to power the unit surely.

 

[Dink]

measuring between red and yellow should always be 0v

you need to go between red or yellow and ground (i tend to use door hinge)

 

[tick]

so if i went between red and ground, what should the reading be?

 

[Dink]

about 12v engine off(if it's not switched with the ignition)

about 14v engine on

 

[tick]

and that'll be for the red and yellow leads both giving a reading of that?

 

[Dink]

yep but only one should give a reading with the engine off

 

[tick]

right ive put the head unit in the car from my wife's car and still isnt working so must be power going to head unit thats at fault. ive checked the fuse in the fuse pannel which is fine , but is there another fuse anywhere that might be involved?

 

[tick]

got it sorted lads, was the circuit breaker fuse that had blown!! s'pose it helps when you read the manual!! Thanks for help