Horn
10-05-09, 11:01 PM
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Horn
When ever i press the horn buttons on the steering wheel, i hear a faint clicking sound. Can anyone tell me whats wrong, the previous owner had the green w/ orange wires cut from the cpu and one of the plugs under the steering wheel, before there was no sound after connecting the wires i get the clicking sound?????
10-07-09, 03:20 AM
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You press the horn button. That puts a ground on a relay in the CPU. Horn honks when the relays contacts make.
The click you hear is the HORN RELAY inside the CPU clicking when it pulls in.
If the relay clicks, and the horn does not honk, either the horns are disconnected or the signal out of the relay to the horns is open. Could be open because the solder joints on the electrical contacts at the plugs are crummy and the solder needs to be reflowed with a soldering iron. Maybe.
Horn power is from the STOP fuse. IF the brake lights work, the fuse is good and the fuse is not the problem.
Green/Orange is the ground wire from the horn button to the CPU and then to the Horn relay inside the CPU.
Red/Green is the wire from the CPU to the horns.
Green/White is the power from the STOP fuse.
If the CPU plug is pulled off and a jumper wire is put b/t the G/W and the G/R, the horn works proving the fuse is good and the horns are connected up at the horns. Proves the CPU is the problem Either cold solder joints or bad contacts on the Horn relay. Usually cold solder joints in the area where the elect plug connects to the CPU.
Wiggle the wires on THAT plug on the CPU and see if the horn works while you push the horn button. If it works intermittently then you have cold solder joints at the plug attachment area.l
The click you hear is the HORN RELAY inside the CPU clicking when it pulls in.
If the relay clicks, and the horn does not honk, either the horns are disconnected or the signal out of the relay to the horns is open. Could be open because the solder joints on the electrical contacts at the plugs are crummy and the solder needs to be reflowed with a soldering iron. Maybe.
Horn power is from the STOP fuse. IF the brake lights work, the fuse is good and the fuse is not the problem.
Green/Orange is the ground wire from the horn button to the CPU and then to the Horn relay inside the CPU.
Red/Green is the wire from the CPU to the horns.
Green/White is the power from the STOP fuse.
If the CPU plug is pulled off and a jumper wire is put b/t the G/W and the G/R, the horn works proving the fuse is good and the horns are connected up at the horns. Proves the CPU is the problem Either cold solder joints or bad contacts on the Horn relay. Usually cold solder joints in the area where the elect plug connects to the CPU.
Wiggle the wires on THAT plug on the CPU and see if the horn works while you push the horn button. If it works intermittently then you have cold solder joints at the plug attachment area.l
10-07-09, 05:58 PM
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HAILERS Thank you very much. When i connected the G/W with G/O the horn works so now i know the cpu is the problem. Say if i up load a pic of the cpu could u tell me what connection to fix??
10-07-09, 06:16 PM
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Well the CPU is made of of (I think) three circuit boards. The elect plug you've been messing with is attached to a circuit board. That board needs to be removed, then you look at the prongs that the plug was attached to and reflow the solder that attaches the prongs to the board. Something like that.
You have to remove the CPU and sort of look at it to tell how to remove that board. I think if you look at it for a while you'll figure out how to remove the circuit board.
Mazdatrix sells the boards and here is a jpg from that site. Tooooo rich for my blood.
The second jpg came from the FSM section called BODY ELECTRICAL.
You have to remove the CPU and sort of look at it to tell how to remove that board. I think if you look at it for a while you'll figure out how to remove the circuit board.
Mazdatrix sells the boards and here is a jpg from that site. Tooooo rich for my blood.
The second jpg came from the FSM section called BODY ELECTRICAL.
10-07-09, 06:25 PM
#6
commit(rnd()&sense-acts)
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/brake-lights-not-working-88-vert-721447/
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