Need help with radio problem
Thread Starter
Teching In
Joined: Dec 2004
Posts: 41
Likes: 0
Need help with radio problem I have a 1995 formula and when you have the radio on and you shut the car off the radio stays on (normal) when you open the door the radio turns off (normal) but when you shut the door again with no keys in it the radio comes back on by itself, you have to manually turn it off or it stay on till the battery saver relay shuts it off, i tried changing the stock radio but the problem is still there. door ajar switches work fine. any idears?
TECH Enthusiast
Joined: Sep 2005
Posts: 717
Likes: 0
From: Georgetown, DE
I doubt it has anything to do with the radio. Sounds to me like a relay malfunction.
NOTE: I've never seen a schematic, so this is purely guesswork.
I presume there is a control relay with a feedback loop circuit. When the car is on, the relay is energized to turn on the accessory power. When key is removed, the relay stays energized (keeping the power on to the radio) until the feedback circuit is broken by either one of the door switches or by a timer. From your description, the door switch is interupting the relay circuit as it's supposed to, and the relay de-energizes removing power. But for some reason, when the door is closed, the relay coil circuit is completed again and the relay turns power back on. That means the feedback loop is still hot, even though the relay was de-energized while the door was open. My guess is that there is probably a short somewhere in the vacinity of that control relay.
NOTE: I've never seen a schematic, so this is purely guesswork.
I presume there is a control relay with a feedback loop circuit. When the car is on, the relay is energized to turn on the accessory power. When key is removed, the relay stays energized (keeping the power on to the radio) until the feedback circuit is broken by either one of the door switches or by a timer. From your description, the door switch is interupting the relay circuit as it's supposed to, and the relay de-energizes removing power. But for some reason, when the door is closed, the relay coil circuit is completed again and the relay turns power back on. That means the feedback loop is still hot, even though the relay was de-energized while the door was open. My guess is that there is probably a short somewhere in the vacinity of that control relay.
Joined: Nov 2003
Posts: 11,328
Likes: 344
From: Jacksonville, FL (originally from Toronto Canada)
Originally Posted by HiTechGent
I doubt it has anything to do with the radio. Sounds to me like a relay malfunction.
NOTE: I've never seen a schematic, so this is purely guesswork.
I presume there is a control relay with a feedback loop circuit. When the car is on, the relay is energized to turn on the accessory power. When key is removed, the relay stays energized (keeping the power on to the radio) until the feedback circuit is broken by either one of the door switches or by a timer. From your description, the door switch is interupting the relay circuit as it's supposed to, and the relay de-energizes removing power. But for some reason, when the door is closed, the relay coil circuit is completed again and the relay turns power back on. That means the feedback loop is still hot, even though the relay was de-energized while the door was open. My guess is that there is probably a short somewhere in the vacinity of that control relay.
NOTE: I've never seen a schematic, so this is purely guesswork.
I presume there is a control relay with a feedback loop circuit. When the car is on, the relay is energized to turn on the accessory power. When key is removed, the relay stays energized (keeping the power on to the radio) until the feedback circuit is broken by either one of the door switches or by a timer. From your description, the door switch is interupting the relay circuit as it's supposed to, and the relay de-energizes removing power. But for some reason, when the door is closed, the relay coil circuit is completed again and the relay turns power back on. That means the feedback loop is still hot, even though the relay was de-energized while the door was open. My guess is that there is probably a short somewhere in the vacinity of that control relay.
If your courtesy lights are working properly then you can be sure that the door switches and ground signal to the BCM are working (the BCM also controls the courtesy lights). I doubt this will help but try it just to be sure - shut off car, open door, close door, and check if the power windows work as well as the radio. If so then it's probably your BCM. If not then there's something wrong with the radio connections because the RAP should work the same for windows and radio.
Thread Starter
Teching In
Joined: Dec 2004
Posts: 41
Likes: 0
I tried the windows and they too also work when the radio comes back on and all the door swiches are definitly good. Do you think that it is a bad body control module or the relay and is the relay even servicable?
Joined: Nov 2003
Posts: 11,328
Likes: 344
From: Jacksonville, FL (originally from Toronto Canada)
There is no separate relay - the RAP function is controlled by the BCM (there is the equivalent of a SPDT relay inside the BCM but it is not serviceable). It really sounds like the BCM is the problem. There are things you could check but they would only confirm what you've already done. For example, you can check the dark blue wire in the black 6-pin connector at the BCM. That is the RAP output wire that powers the COURTESY fuse and the power window circuit breaker. But you already know that there will be power there because you have a radio playing with the ignition off.
I would guess that the BCM's internal 10-minute RAP timer is continuing to run regardless of whether a door has been opened. That would explain why the radio goes back on when you close the door.
I would guess that the BCM's internal 10-minute RAP timer is continuing to run regardless of whether a door has been opened. That would explain why the radio goes back on when you close the door.
