SE electrical gurus Riddle me this?
09-22-06, 03:19 AM
#1
SE electrical gurus Riddle me this?
Story is as follows:
Friend was selling his SE, installed a new battery, hooked up the cables right, but turned the battery around 180*. When the hood closed, the hinge shorted on the + post, overheated the battery cables, blew some fusible links. 6" of the + &- cables coating were melted together, but I don't think they shorted to each other directly. Replaced the links with fuses, new + cable and a used - cable. New owner fired it up, drove it home, no problems.
A couple of weeks later he drops off the car, tosses me the keys and tells me everytime he puts it in reverse, it blows the engine fuse under the dash, kills, the fuel pump, engine dies.
I figure I didn't look over all the wiring enough and missed an overheated/melted wire. So I start at the tranny and check the wiring under there, it all looks good. Car was wired for a trailer at one time, harness was a big pile of spagetti sitting in the spare tire well, remove all of that, check the tail light/back-up wiring. No change. Remove back-up light bulbs, no change.
Go back to the tranny and unplug each of the 3 pairs of wires for the reverse, neutral, and inhibitor switches, no change. Remove the shifter cover looking for wires that may be shorting, none found. At this point, I did notice a change as to when the fuse blows. It's not just blowing when going into reverse, it's blowing when the shifter is moved to the 5th/reverse gate, before even going into either gear. It may have been doing this from the beginning as I was shifting into revese quickly before and had not tried 5th.
Getting interesting yet?
I'm running out of ideas as where to look and have run out of 20 amp fuses. At this point in time, 15 amp fuses blow as soon as turn the ignition on. Before that, I could start the engine with a 15 amp and it didn't blow until I moved the shifter to the 5th/reverse gate.
I have not found any bad wires other than one of the inhibitor wires had been spliced, (wire nut), and the O2 wire seems to be pinched between the block and the injector hold down under the intake manifold where I can feel it, but not see it. The last owner must have done that when he replaced the injector clips. I am not sure what, or if, there is a relationship between the O2 sensor and the 5th/reverse gate, backup or inhibitor switches.
Wiring and electrical is not one of my strong points, so I could use a little help here guys and gals. Sorry for writing a novel, but the solution is somewhere in the details provided, I hope.
Scott.
Friend was selling his SE, installed a new battery, hooked up the cables right, but turned the battery around 180*. When the hood closed, the hinge shorted on the + post, overheated the battery cables, blew some fusible links. 6" of the + &- cables coating were melted together, but I don't think they shorted to each other directly. Replaced the links with fuses, new + cable and a used - cable. New owner fired it up, drove it home, no problems.
A couple of weeks later he drops off the car, tosses me the keys and tells me everytime he puts it in reverse, it blows the engine fuse under the dash, kills, the fuel pump, engine dies.
I figure I didn't look over all the wiring enough and missed an overheated/melted wire. So I start at the tranny and check the wiring under there, it all looks good. Car was wired for a trailer at one time, harness was a big pile of spagetti sitting in the spare tire well, remove all of that, check the tail light/back-up wiring. No change. Remove back-up light bulbs, no change.
Go back to the tranny and unplug each of the 3 pairs of wires for the reverse, neutral, and inhibitor switches, no change. Remove the shifter cover looking for wires that may be shorting, none found. At this point, I did notice a change as to when the fuse blows. It's not just blowing when going into reverse, it's blowing when the shifter is moved to the 5th/reverse gate, before even going into either gear. It may have been doing this from the beginning as I was shifting into revese quickly before and had not tried 5th.
Getting interesting yet?
I'm running out of ideas as where to look and have run out of 20 amp fuses. At this point in time, 15 amp fuses blow as soon as turn the ignition on. Before that, I could start the engine with a 15 amp and it didn't blow until I moved the shifter to the 5th/reverse gate.
I have not found any bad wires other than one of the inhibitor wires had been spliced, (wire nut), and the O2 wire seems to be pinched between the block and the injector hold down under the intake manifold where I can feel it, but not see it. The last owner must have done that when he replaced the injector clips. I am not sure what, or if, there is a relationship between the O2 sensor and the 5th/reverse gate, backup or inhibitor switches.
Wiring and electrical is not one of my strong points, so I could use a little help here guys and gals. Sorry for writing a novel, but the solution is somewhere in the details provided, I hope.
Scott.
09-22-06, 02:13 PM
#4
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Do these have the master on/off switch for the cruise located in the console? S2 did, but I haven't messed with any S3 w/cruise.
Perhaps the problem is in the under-console wiring somewhere, and is affected by the movement of the shifter? I certainly cannot think of any other explanation for the fuse to blow, just by moving the shifter.
Is there *any* chance that underhood wiring could get anywhere near the forward end of the shifter? I know it sounds *almost* stupid, since the forward end of the shifter is inside the case of the trans. But I cannot come up with any other idea, unless there is some strange switch on either end of the shift rail.
Damn sure got me stumped......
Paul.
Perhaps the problem is in the under-console wiring somewhere, and is affected by the movement of the shifter? I certainly cannot think of any other explanation for the fuse to blow, just by moving the shifter.
Is there *any* chance that underhood wiring could get anywhere near the forward end of the shifter? I know it sounds *almost* stupid, since the forward end of the shifter is inside the case of the trans. But I cannot come up with any other idea, unless there is some strange switch on either end of the shift rail.
Damn sure got me stumped......
Paul.
09-22-06, 02:26 PM
#5
Right now, all the tranny connections are unhooked, still blows the fuse. I need to sit down and study the wiring diagrams better. I hadn't thought about a tie in between the cruise control and 5th gear. When the fuse blows, I still have the clutch in. It's blowing as soon as the shifter hits the far right gate, don't even get a chance to go to 5th or reverse.
Thanks for the input, keep it coming guys. I'm afraid it's going to be a long night in the shop.
Thanks for the input, keep it coming guys. I'm afraid it's going to be a long night in the shop.
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09-22-06, 02:58 PM
#10
callin' tokyo
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Well something is using an extra 5 amps of power continually it seems. You could create a catastrophic failure by shorting the fuse out and then looking for the smoke/fire...
Does the battery drain itself? (Do you have a meter?)
Does the battery drain itself? (Do you have a meter?)
09-22-06, 03:04 PM
#11
well it seems to me that the shifter somewhere is your problem. i bet if you dug deeper you might find that some wire has shorted to whatever it is that the shifter linkages are moving to once you hit that 5th/reverse area.
09-22-06, 03:09 PM
#12
callin' tokyo
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As far as I know, there are only 3 sets of wires by the shifter, the radio, the power windows and an auto transmission wire (that should be floating, unplugged). The cruise control master on/off switch is on the dash by the steering wheel.
09-22-06, 03:16 PM
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Dom, something you said just reminded me. There are 2 sets of wires for an auto, one for the lights, and one set for overdrive on/off. My sis has an 85 GS auto, and it has the O/D on/off switch on the shifter surround. Her car doesn't have cruise, which is why I am not familiar with the location of a master switch.
Maybe that will help, I dunno.
Maybe that will help, I dunno.
09-22-06, 03:50 PM
#14
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The ignition (which is on a 20 amp fuse) is fed from a line which also feeds the reverse lights (15 amp fuse) and the power windows (30 amps). Remove those 2 fuses and test...
09-22-06, 04:56 PM
#15
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The 20A circuit coming off of the ignition switch controls the Cruise Control. It has an assortment of controls and sensors, to include the Air Supply Valve, ACV Relay, and the Over Top Switch. I would check the ACV Relay. The OTS grounds out through this relay. Probably doesn't help much.............good luck
09-22-06, 06:30 PM
#16
I think I found the problem. Got it to start, and go into 5th and reverse without blowing the engine fuse. Need to go back and reconnect the wires that are still unplugged, reseal and install one of the tail lights to make sure it's fixed.
I doubt anyone could guess what the issue was, but here is a hint. The battery wasn't charging. I'll post a pic later tonight of what I found. In the mean time, keep guessing away. I'll award a cookie or 10 forum bucks to whoever guesses right. lol
I doubt anyone could guess what the issue was, but here is a hint. The battery wasn't charging. I'll post a pic later tonight of what I found. In the mean time, keep guessing away. I'll award a cookie or 10 forum bucks to whoever guesses right. lol
09-22-06, 06:37 PM
#17
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Dunno, but it *could* even be similar to an issue I found in a freinds SA. Unhooked the radio antenna, and damned if the fuel wouldn't shut off when the lights were turned on, and the turn signals would all blink (both sides). Plugged the coax back into the antenna, and problem went away. I know it has a bad ground *somewhere* in the body wiring, but haven't took the time to hunt it down, since it has a bandaid on it...... Bad engine bearings doesn't hurt, either.......
09-22-06, 07:52 PM
#18
V8 RX-7
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This problem is clearly after the power has reached the reverse light switch, and where does the current flow to after the switch? back to the battery on the ground, so whats next after the switch?...
The ground from the battery negative to the engine block. i'm almost positive (haha) thats the problem.
The reverse light switch trigger needs to ground, goes through the motor to the engine block ground wire. This 6awg wire is black with a yellow stripe on my 84 se, but be aware mazda liked to change the colors of the curcuits even inside a model year, just like big brother ford even at an early age
the engine block ground runs up to the chassis ground on the drivers side inner strut tower and then to the battery negative.
you can leave the cable intact if you like, because the following method I suggest is a much more direct (read better) route.
directly with ring terminals on 4 awg or bigger run from one of the starter mounting bolts to the battery negative. this is close to the the reverse light switch and the starter which can draw a lot of current if the brushes are worn or the cables are resistive, which is often the case with a car that is almost at the age of a responsible adult
The ground from the battery negative to the engine block. i'm almost positive (haha) thats the problem.
The reverse light switch trigger needs to ground, goes through the motor to the engine block ground wire. This 6awg wire is black with a yellow stripe on my 84 se, but be aware mazda liked to change the colors of the curcuits even inside a model year, just like big brother ford even at an early age
the engine block ground runs up to the chassis ground on the drivers side inner strut tower and then to the battery negative.you can leave the cable intact if you like, because the following method I suggest is a much more direct (read better) route.
directly with ring terminals on 4 awg or bigger run from one of the starter mounting bolts to the battery negative. this is close to the the reverse light switch and the starter which can draw a lot of current if the brushes are worn or the cables are resistive, which is often the case with a car that is almost at the age of a responsible adult
09-22-06, 07:58 PM
#19
Success
In the following pic, the 2 connectors were, well, connected. I have no idea what the female end is for, as far as I know, it's another one of those connectors with no home, life or place to go. The male connector goes to the alternator. How or why connecting the 2 produced the issue I was dealing with, I have no idea and am not sure if I even want to know.
Apparently when the po replaced the injector clips, he plugged the connectors together. This also explains why he couldn't keep the battery charged. I have found 2 other assembly errors I need to deal with, he broke the wire off of the air temp sensor and pinched the O2 wire between the injector hold down and the block. I will deal with the temp sensor and hope the O2 sensor causes no further problems.
Thanks for all the help guys. Chalk this one up to another odd 7 adventure.
Apparently when the po replaced the injector clips, he plugged the connectors together. This also explains why he couldn't keep the battery charged. I have found 2 other assembly errors I need to deal with, he broke the wire off of the air temp sensor and pinched the O2 wire between the injector hold down and the block. I will deal with the temp sensor and hope the O2 sensor causes no further problems.
Thanks for all the help guys. Chalk this one up to another odd 7 adventure.
09-22-06, 09:13 PM
#20
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I'm not sure what that connector is for but u remember having it not connected when my se ran fine, it is tied in with the injector harness that comes from the passenger side. I could be power steering level sensor, because i didn't have p/s, but if so i would imagine it would be included with the drivers side harness
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