Stuck in Flagstaff - Back up light wires blowing GUAGE fuse
#1
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Stuck in Flagstaff - Back up light wires blowing GUAGE fuse
Aloha YT,
Stuck in Flagstaff trying to figure this out. I am on my way to school out east and need to be on the road asap. I bought a used 93 4runner yesterday (3VZE, 5sp, 4WD) and when I got off the road in Flagstaff today I noticed my gas guage was not moving after filling up: nor were the tach/speedometer/ac/heat/windows working. I checked and the GUAGE fuse was blown. Replaced the 10A GUAGE fuse and as soon as I shifted into reverse, POP. I researched the issue and it appears to be the back up light circuit grounding somewhere (I went through a few more fuses to make sure, as soon as the stick shifts to reverse POP). I removed the backup light housings and checked the wires. While old, they seem to be solid and notshorting anywhere. I got under the truck and checked the wires by the transmission (still not clear on what is what down there as I cant find images of the connector referenced in the FSM) and no wires seem to be nicked/pulled from the connector seating/grounding anywhere. I am in a jam and would appreciate any help guys. Mahalo in advance gentlemen. It's sleeting out now, I will post pics first thing in the morning.
-R
Stuck in Flagstaff trying to figure this out. I am on my way to school out east and need to be on the road asap. I bought a used 93 4runner yesterday (3VZE, 5sp, 4WD) and when I got off the road in Flagstaff today I noticed my gas guage was not moving after filling up: nor were the tach/speedometer/ac/heat/windows working. I checked and the GUAGE fuse was blown. Replaced the 10A GUAGE fuse and as soon as I shifted into reverse, POP. I researched the issue and it appears to be the back up light circuit grounding somewhere (I went through a few more fuses to make sure, as soon as the stick shifts to reverse POP). I removed the backup light housings and checked the wires. While old, they seem to be solid and notshorting anywhere. I got under the truck and checked the wires by the transmission (still not clear on what is what down there as I cant find images of the connector referenced in the FSM) and no wires seem to be nicked/pulled from the connector seating/grounding anywhere. I am in a jam and would appreciate any help guys. Mahalo in advance gentlemen. It's sleeting out now, I will post pics first thing in the morning.
-R
Last edited by surf4life; 05-22-2019 at 10:05 AM. Reason: Update trans
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swampedout (09-22-2020)
#2
Aloha YT,
Stuck in Flagstaff trying to figure this out. I am on my way to school out east and need to be on the road asap. I bought a used 93 4runner yesterday (3VZE - 4WD) and when I got off the road in Flagstaff today I noticed my gas guage was not moving after filling up: nor were the tach/speedometer/ac/heat/windows working. I checked and the GUAGE fuse was blown. Replaced the 10A GUAGE fuse and as soon as I shifted into reverse, POP. I researched the issue and it appears to be the back up light circuit grounding somewhere (I went through a few more fuses to make sure, as soon as the stick shifts to reverse POP). I removed the backup light housings and checked the wires. While old, they seem to be solid and notshorting anywhere. I got under the truck and checked the wires by the transmission (still not clear on what is what down there as I cant find images of the connector referenced in the FSM) and no wires seem to be nicked/pulled from the connector seating/grounding anywhere. I am in a jam and would appreciate any help guys. Mahalo in advance gentlemen. It's sleeting out now, I will post pics first thing in the morning.
-R
Stuck in Flagstaff trying to figure this out. I am on my way to school out east and need to be on the road asap. I bought a used 93 4runner yesterday (3VZE - 4WD) and when I got off the road in Flagstaff today I noticed my gas guage was not moving after filling up: nor were the tach/speedometer/ac/heat/windows working. I checked and the GUAGE fuse was blown. Replaced the 10A GUAGE fuse and as soon as I shifted into reverse, POP. I researched the issue and it appears to be the back up light circuit grounding somewhere (I went through a few more fuses to make sure, as soon as the stick shifts to reverse POP). I removed the backup light housings and checked the wires. While old, they seem to be solid and notshorting anywhere. I got under the truck and checked the wires by the transmission (still not clear on what is what down there as I cant find images of the connector referenced in the FSM) and no wires seem to be nicked/pulled from the connector seating/grounding anywhere. I am in a jam and would appreciate any help guys. Mahalo in advance gentlemen. It's sleeting out now, I will post pics first thing in the morning.
-R
This light is triggered by a sensor on the trans. You didn't mention whether or not it's a 5sp but I would start at the sensor on the transmission and work my way back looking for shorts, could also pull the plug on it and not use backup lights for now so you can keep all the others.
On the R150F 5 speed trans in my 1993 it's on the passenger side of the transmission.
#3
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Thread Starter
This light is triggered by a sensor on the trans. You didn't mention whether or not it's a 5sp but I would start at the sensor on the transmission and work my way back looking for shorts, could also pull the plug on it and not use backup lights for now so you can keep all the others.
On the R150F 5 speed trans in my 1993 it's on the passenger side of the transmission.
On the R150F 5 speed trans in my 1993 it's on the passenger side of the transmission.
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Personally, I'd first pull the taillights assemblies, disconnect both (R5 and R6, 6-pin connectors), then risk a fuse. Then plug them back in one at a time. It seems more likely to me that the short to ground would be back in the housings (lots of wire exposed to the elements) than in the reverse switch itself. More importantly, these tests would be easier to do. If disconnecting the taillight assemblies doesn't stop the fuse from blowing, then the short is somewhere between the reverse switch and the taillight assembly.
Last edited by scope103; 05-22-2019 at 09:40 AM.
#5
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Personally, I'd first pull the taillights assemblies, disconnect both (R5 and R6, 6-pin connectors), then risk a fuse. Then plug them back in one at a time. It seems more likely to me that the short to ground would be back in the housings (lots of wire exposed to the elements) than in the reverse switch itself. More importantly, these tests would be easier to do. If disconnecting the taillight assemblies doesn't stop the fuse from blowing, then the short is somewhere between the reverse switch and the taillight assembly.
#6
Registered User
Thread Starter
This light is triggered by a sensor on the trans. You didn't mention whether or not it's a 5sp but I would start at the sensor on the transmission and work my way back looking for shorts, could also pull the plug on it and not use backup lights for now so you can keep all the others.
On the R150F 5 speed trans in my 1993 it's on the passenger side of the transmission.
On the R150F 5 speed trans in my 1993 it's on the passenger side of the transmission.
#7
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Thread Starter
I checked the drivers side back up lights with a voltmeter with all 4 bulbs removed, The smaller bulb terminals are shorted (green & white/black wires) yet the larger bulbs are not (red yellow & white black)
Last edited by surf4life; 05-22-2019 at 11:32 AM.
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#9
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You've prevented the backup switch from connecting to the short, which should be enough to get you out of Flagstaff.
But you still haven't found the short. According to my EWD, the G and W-B wires are to the tail lights Since they are all connected in parallel, checking the resistance on one (or two) sockets will just measure the resistance of the remaining bulbs. 14.1 ohms sounds like the right number. The stop lights are G-W to W-B, and the turn signals are G-B and G-Y to W-B. Last, the Backup Lights (the ones you're interested in), show as R-B to W-B.
I'll bet the R-W wire on your now-disconnected backup switch is shorted to ground. Assuming your backup bulbs are connected to R-Y, and your test indicates that's not shorted to ground, I'll bet it's disconnected from the backup switch, and where that disconnect takes place, the wire from the backup switch is shorted to ground.
The oil on the switch is not a good thing, but I doubt the switch or the oil is your problem. You can test the resistance to ground on both switch terminals (should be infinite). The B-O wire in the connector will have battery voltage with key-on, and the R-W, which SHOULD go to the lamps in back, will show a short to ground.
But you still haven't found the short. According to my EWD, the G and W-B wires are to the tail lights Since they are all connected in parallel, checking the resistance on one (or two) sockets will just measure the resistance of the remaining bulbs. 14.1 ohms sounds like the right number. The stop lights are G-W to W-B, and the turn signals are G-B and G-Y to W-B. Last, the Backup Lights (the ones you're interested in), show as R-B to W-B.
I'll bet the R-W wire on your now-disconnected backup switch is shorted to ground. Assuming your backup bulbs are connected to R-Y, and your test indicates that's not shorted to ground, I'll bet it's disconnected from the backup switch, and where that disconnect takes place, the wire from the backup switch is shorted to ground.
The oil on the switch is not a good thing, but I doubt the switch or the oil is your problem. You can test the resistance to ground on both switch terminals (should be infinite). The B-O wire in the connector will have battery voltage with key-on, and the R-W, which SHOULD go to the lamps in back, will show a short to ground.
Last edited by scope103; 05-22-2019 at 03:11 PM.
#10
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Thread Starter
You've prevented the backup switch from connecting to the short, which should be enough to get you out of Flagstaff.
But you still haven't found the short. According to my EWD, the G and W-B wires are to the tail lights Since they are all connected in parallel, checking the resistance on one (or two) sockets will just measure the resistance of the remaining bulbs. 14.1 ohms sounds like the right number. The stop lights are G-W to W-B, and the turn signals are G-B and G-Y to W-B. Last, the Backup Lights (the ones you're interested in), show as R-B to W-B.
I'll bet the R-W wire on your now-disconnected backup switch is shorted to ground. Assuming your backup bulbs are connected to R-Y, and your test indicates that's not shorted to ground, I'll bet it's disconnected from the backup switch, and where that disconnect takes place, the wire from the backup switch is shorted to ground.
The oil on the switch is not a good thing, but I doubt the switch or the oil is your problem. You can test the resistance to ground on both switch terminals (should be infinite). The B-O wire in the connector will have battery voltage with key-on, and the R-W, which SHOULD go to the lamps in back, will show a short to ground.
But you still haven't found the short. According to my EWD, the G and W-B wires are to the tail lights Since they are all connected in parallel, checking the resistance on one (or two) sockets will just measure the resistance of the remaining bulbs. 14.1 ohms sounds like the right number. The stop lights are G-W to W-B, and the turn signals are G-B and G-Y to W-B. Last, the Backup Lights (the ones you're interested in), show as R-B to W-B.
I'll bet the R-W wire on your now-disconnected backup switch is shorted to ground. Assuming your backup bulbs are connected to R-Y, and your test indicates that's not shorted to ground, I'll bet it's disconnected from the backup switch, and where that disconnect takes place, the wire from the backup switch is shorted to ground.
The oil on the switch is not a good thing, but I doubt the switch or the oil is your problem. You can test the resistance to ground on both switch terminals (should be infinite). The B-O wire in the connector will have battery voltage with key-on, and the R-W, which SHOULD go to the lamps in back, will show a short to ground.
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jazz1 (05-23-2019)
#11
Nice glad that quick fix worked.
You can try replacing the factory switch (mine was shot) or cleaning it up but it sounds like you're going to be tracing some wires to find your short (unless the plug itself for the bulb is shot but that's easy enough to see).
Goodluck and glad you're moving again!
Some wiring help:
You can try replacing the factory switch (mine was shot) or cleaning it up but it sounds like you're going to be tracing some wires to find your short (unless the plug itself for the bulb is shot but that's easy enough to see).
Goodluck and glad you're moving again!
Some wiring help:
#12
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The reverse lights switch commonly short out internally. They usually will either short to ground or stick the lights on all the time. Unplug the switch, and jump the connector with a paper clip. If the fuse blows, its an issue further down the line. If the lights work, put a new switch in it.
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ZTEC (05-24-2019)
#13
It looks like the back up switch is leaking internally causing the short. Replace the switch and check the trans fluid level, I think it's a 24 mm for the fill plug on the drivers side opposite of the back up switch. This same thing happened to me when I was traveling to Hawaii last month. I replaced the swich, fixed the leak and the short.
Last edited by ZTEC; 05-24-2019 at 01:38 PM.
#14
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Thread Starter
It looks like the back up switch is leaking internally causing the short. Replace the switch and check the trans fluid level, I think it's a 24 mm for the fill plug on the drivers side opposite of the back up switch. This same thing happened to me when I was traveling to Hawaii last month. I replaced the swich, fixed the leak and the short.
#15
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I am resurrecting this thread as now I need to fix this for safety inspection. For the year I was on the mainland I just kept the reverse switch on the transfer case disconnected and zip tied out of the way. Never got hassled for it. Shipped my truck cross country/over the ocean after the Rona came and have been having issues ever since. Never ship your yota if you don't have to! Already done CV half shafts, sway bar links, the starter, brake booster, brakes and now onto this. Back home in Hawai'i and of course they need my reverse lights to work in order to pass safety. I am going to catch up on everyone's suggestions and post updates here throughout the week. As always, I am super grateful for all you guys and all the help you have provided over the years. You are all truly legends. Mahalo nui loa.
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RAD4Runner (09-23-2020)
#16
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So by unpluging the switch you've eliminated half the circuit. The problem is in the wiring between the switch and the light bulbs. I think you've even said that you could see that it was shorted previously. I personally would just run a new wire from the switch to the socket at the tail lights.
#17
Registered User
Thread Starter
The reverse lights switch commonly short out internally. They usually will either short to ground or stick the lights on all the time. Unplug the switch, and jump the connector with a paper clip. If the fuse blows, its an issue further down the line. If the lights work, put a new switch in it.
Last edited by surf4life; 09-26-2020 at 12:59 PM.
#18
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Thread Starter
I'm going to try this right now. First I'm going to clean off the switch, connector, and transfer casing around the switch. I will post an update once I run this test. Thank you all for continuing to assist on this thread. Never ceases to amaze me how helpful you guys are.
#19
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Thread Starter
Problem Solved: Replaced the switch and topped off the transfer case with gl5 75w90 gear oil (they didn't have gl4). Reverse lights working perfectly now and all good. Big mahalo to everyone who posted on this thread to help. Aloha!
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