When i press the horn my stereo turns off then on again and other probs

[Pikamix91]

I have just installed a new stereo in my 1990 fiesta and noticed that wen i press the horn, the stereo cuts out and resets itself then turns back on.
Also my rear window wiper only works wen it wants to and not sure why its like that, ive "sanded" down the four pins that touch the contact plate on the boot but still not working.
Plus the interior light doesnt work wen the door opens anymore, ive checked the fuses and there ok, but it works wen u change the switch to stay on constantly.
Oh last of all, wen its idling its at 1000revs and i put it in drive the revs drop badly and after a while wen i stop the car, it stalls.
Someone gimmy sum advice, this car is driving me mad.

[748rhydhir]

remove the newly installed stereo & see if the faults disappear.

[Pikamix91]

Yeah 748rhydhir i did that and it did stop the problem but this stereo is the nuts and its fitted in the exact same way as the previous one but this problem occurs..... U got any answers for my other probs?
Thanks

[Pikamix91]

Alrite people, just updating the question. Ive managed to fix the stereo problem, i jus rewired it without the ISO adapter, but still having problems with the rear wiper, interior light and revs.
Cheers

[society]

"When i press the horn my stereo turns off then on again and other probs"

It's possess. You've manage to chase the ghost from one area to another area. :-)

[Pikamix91]

Cheers BOL10X. Ive cleaned well sanded down the contacts on the boot but didnt think of the wires, good point. Wen it stops raining i will ava look. Have you got any other ideas of how to clean the contacts, as i used sand paper?
Cheers

[craft1948]

Whenever I put my TV on standby using the remote the sound system comes on...I'm not really bothered but just thought I'd mention it..............