Electrical problems |
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Electrical problems |
watsonrx13 |
Aug 13 2008, 07:01 PM
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#1
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Advanced Member Group: Members Posts: 2,734 Joined: 18-February 03 From: Plant City, FL Member No.: 312 Region Association: South East States |
I've been trying to track down an electrical problem with my FI and I've found more problems.
1. When I turn on the ignition switch I blow fuse #9. The Haynes manual says that this fuse powers the turn signals, brake lights and back-up lights. Also, I noticed that the buzzer sounds when I turn on the key, regardless of both doors closed or open. Anyway, I disconnected the brake light switch at the brake pedal, all of the wires to the turn signals and disconnected the back-up light wire at the tranny but the fuse still blows, which then stops the buzzer. 2. No power to the coil. I've replaced the ignition switch with another one, but I'm still not getting any power at the coil. I've checked the continuity between the ignition switch and the coil. I have power to all pin #30s on the relay board in the engine compartment. I have power at the large red wire at the ignition switch. I feel that I'm very close to getting this car running, but with these electrical gremlins I'm extremely frustrated...(IMG:style_emoticons/default/mad.gif) Any suggestions and/or guidance would be greatly appreciated.... -- Rob |
904svo |
Aug 13 2008, 08:05 PM
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#2
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904SVO Group: Members Posts: 1,118 Joined: 17-November 05 From: Woodstock,Georgia Member No.: 5,146 |
Try this remove fuse #9, using a volt meter or trouble light check
1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it) these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following 2. Problem must be on the black/yellow wire ( brake switch) or the red/white wires which power the gauges and the emergency flasher switch if you disconnect these wires and reattatched them one at a time you can find out which wire is causing you a problem which you can track down the problem. hope this helps you |
watsonrx13 |
Aug 14 2008, 04:43 PM
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#3
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Advanced Member Group: Members Posts: 2,734 Joined: 18-February 03 From: Plant City, FL Member No.: 312 Region Association: South East States |
Try this remove fuse #9, using a volt meter or trouble light check 1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it) these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following 2. Problem must be on the black/yellow wire ( brake switch) or the red/white wires which power the gauges and the emergency flasher switch if you disconnect these wires and reattatched them one at a time you can find out which wire is causing you a problem which you can track down the problem. hope this helps you I've have some updated information.... 1. I have 12 v on the black wires .... 2. I found where the wires connect to the brake switch and disconnected them. I disconnected the red/white wires from behind the instrument cluster, but only the one that came off of the main wiring harness. I know that the other red/white wires are in series, so I was hoping that I only had to disconnect the first one in the loop. I ran out of time, before the storm set in, but I'm assuming that I just need to reach behind the dash and disconnect the red/white wire to the emergency flasher? Anyway, with only the emergency flasher connected, I installed the #9 fuse and turned on the ignition, it still blew the switch... I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch.... Thanks again for the assistance.... -- Rob |
swl |
Aug 15 2008, 09:17 AM
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#4
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Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch.... Have a look at the current flow diagram for 1974 usa part 2. The cct we are looking at is on the left hand side of the diagram with the fuse 'S9' near the top of the page and the brake switch 'F' near the center. Power is coming from S9 by way of the bk/yw into a connection cluster of 3 wires. from that connection point power flows to the backup light switch 'F4' by way of the GY/BR (gray brown) wire. This switch is back on your transmission. It looks to me like the red white takes power to 'G9' oil temp indicator and 'G14' volt meter. the black/yellow on the other side of the brake switch takes the power to the lights themselves when the switch is closed. So yes what you are seeing is consistent with the wiring diagram. Suggestions: with power off - Lift the gy/br and rd/wh from that connection point and measure with your ohm meter between ground and each of those wire ends. Also measure from ground to the remaining connector on the switch. You are looking for the branch that measure really low - 1 ohm'ish or lower |
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