Need to know about CPU...
Thread Starter
2nd is the first loser!
Joined: Mar 2007
Posts: 90
Likes: 0
From: Salem, OR
Need to know about CPU...
I need to know what the CPU controls and what the functions are. I have a weird problem w/ my radio and my door warning light flashing while I am driving. The radio wont turn on and turns itself on and off rapidly. Any help or ideas would be great. BTW-I searched and found nothing.
Senior Member
Joined: Apr 2004
Posts: 453
Likes: 0
From: South Jordan UT
I'm pretty sure the CPU doesn't control the radio. As far as I know, it controls the horn, turn signals, and some warning buzzers and lights. Someone may know for sure on the small stuff. if you have a factory radio, they are prone to the cold solder joint thing that is common in the cpu and switch gear. Most people, and me too, feel that just changing the radio is the hot setup because it sucks when it's working right and it rarely works right.
Former Moderator. RIP Icemark.
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
S4 CPU controls:
Horn,
Key lights
Key in door open buzzer
Light on door open buzzer
seat belt not on warnings
Turn signals
brake lights
alternator failure warnings
S5 CPU controls:
Horn,
Key lights
Key in door open buzzer
Light on door open buzzer
seat belt not on warnings
Turn signals
security functions.
High beams (on S5 convertibles).
Radio turning off and on, indicates bad ground or low voltage or a shorted/blown speaker
Horn,
Key lights
Key in door open buzzer
Light on door open buzzer
seat belt not on warnings
Turn signals
brake lights
alternator failure warnings
S5 CPU controls:
Horn,
Key lights
Key in door open buzzer
Light on door open buzzer
seat belt not on warnings
Turn signals
security functions.
High beams (on S5 convertibles).
Radio turning off and on, indicates bad ground or low voltage or a shorted/blown speaker
Thread Starter
2nd is the first loser!
Joined: Mar 2007
Posts: 90
Likes: 0
From: Salem, OR
Hmm....ok. The radio only does it when the door light flashes as well. And my clock now resets itself everytime I restart my car. My horn was honking when I turned my car off so I disconnected it. Anyone else have any ideas? I want to replace the CPU just to make sure there isnt an issue there. Also at the same time my factory alarm quit working as well. Its startin to drive me mad....
Senior Member
Joined: Mar 2007
Posts: 310
Likes: 0
From: USA/Mass
Sounds like you have a short. Possibly your accessory and battery wires tapping/rubbing. When I was installing my radio I screwed up and tapped the wires together and everything went haywire... well until the room fuse blew.
Trending Topics
Thread Starter
2nd is the first loser!
Joined: Mar 2007
Posts: 90
Likes: 0
From: Salem, OR
Something else that is weird...When you turn the key to "ACC" nothing happens, nothing gets power that should.....i.e.-radio. I have replaced the ign wiring already with a brand new one from Mazda. Im runnin out of ideas. My wiring harness is unwrapped mostly at the moment. I havent unwrapped the one in the interior yet though. Does anyone have any idea what might have happened? I cant seem to find any crossed wires.
Former Moderator. RIP Icemark.
Joined: Apr 2001
Posts: 25,896
Likes: 24
From: Rohnert Park CA
Thread Starter
2nd is the first loser!
Joined: Mar 2007
Posts: 90
Likes: 0
From: Salem, OR
I checked it w/ a multimeter. Im not an idiot. It showed over 12v. I found that the memory wire for the radio is connected to the part of the wire harness that has a short or an odd ground problem. I rewired a new wire to the battery for the radio. I still have to sort out why the alarm, door warning light, and the interior lights are inop. I didnt list voltage because I knew it wasnt the issue.
Winter sucks
Joined: Jan 2004
Posts: 3,083
Likes: 0
From: Newberg, Oregon
Somebody miss their yoga class? 
RX7_Racer: Make sure you fuse-protect that new radio wire you ran. If you don't, you may end up with a bigger headache than you currently have now.
Also... You live in salem.. Nice to see another Oregon player. I'm in Newberg... a hop skip and a jump away.
RX7_Racer: Make sure you fuse-protect that new radio wire you ran. If you don't, you may end up with a bigger headache than you currently have now.
Also... You live in salem.. Nice to see another Oregon player. I'm in Newberg... a hop skip and a jump away.
Rotary Enthusiast
Joined: Oct 2002
Posts: 905
Likes: 0
From: houston
out of curiousity..you did check the fuses under the driver's side right? ...there should be a 7.5 fuse that controls the interior lights....i just changed mine and my problem is solved. it should be the one that is sitting higher then the rest of them.
Last edited by apreludem; May 14, 2007 at 09:23 AM.
Thread Starter
2nd is the first loser!
Joined: Mar 2007
Posts: 90
Likes: 0
From: Salem, OR
I took the fuse out and my tach and dash instruments quick working. So I figured that the fuse was fine. I havent tried to replace it. The radio works great and is still fused through the fuse box because it still turns on only when you turn the key to "ACC"....My door warning light is now off because I turned my interior light to the "OFF" position instead of the "ON WHEN DOOR IS OPEN" position.
Passenger
Posts: n/a
From: So. CaL
the same EXACT problem had just happend to me today!
first, i noticed my radio NOT WANTING TO WORK! i said "EFF IT" because i didnt have time to deal with it.
second, i noticed the my door lights weren't ON when i opened my door, and neither of the dome lights were working. however the light in the glove box works...
third, NOTHING HAPPENS when the key is turned to ACC.
i was driving around at night with the lights on, and i noticed the same sort of beeping that comes on when the door's open with the lights on... and that's when i found out the "door ajar" light on the idiot cluster was stuck. WTF?!
i want to fix everything once day light arrives... i truly hope it's that 7.5 fuse!!
first, i noticed my radio NOT WANTING TO WORK! i said "EFF IT" because i didnt have time to deal with it.
second, i noticed the my door lights weren't ON when i opened my door, and neither of the dome lights were working. however the light in the glove box works...
third, NOTHING HAPPENS when the key is turned to ACC.
i was driving around at night with the lights on, and i noticed the same sort of beeping that comes on when the door's open with the lights on... and that's when i found out the "door ajar" light on the idiot cluster was stuck. WTF?!
i want to fix everything once day light arrives... i truly hope it's that 7.5 fuse!!
Thread
Thread Starter
Forum
Replies
Last Post
demongo
1st Generation Specific (1979-1985)
7
Oct 29, 2012 03:16 PM
