Cadillac - No Reverse Lights
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Date: 2020-08-05
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Comments and reviews: 10
Bryan
Just tossing this out there. At 17: 40 or so you repeatedly install and remove the relay. I know this is an old video.
Instead of believing me, some day when you have the pico scope out, probe the 85 wire that grounds the relay coil. Get the wire end, not the relay end, and do the same thing.
The point is, the circuitry has inductive clamping/output protection/whatever you want to call it that is not being allowed to do it's job (because the relay is unplugged. Some relays are fitted with suppression diodes internally, this doesn't apply to what I am talking about.
When you do what you did, you may or may not see voltage spikes on the wire, that would depend on the driver they used and the efficacy of the suppression circuitry in that wire.
The overall point is that you are able to get away with doing that because of improvements in output protection that have occurred over the years with the availability of better parts and better design. With that said, that hasn't always been the case. Do what you did to an Allison transmission controller from the early days, and you would be buying a new ECU (back when they cost 3 grand) Same thing with probing the outputs with a test light instead of a meter. Too much load (incandescent test light) smokes the transistor. Not good enough inductive suppression smokes it too.
I guess what I am really trying to say is that by doing that, you are relying on the technology to protect you against what are essentially undefined conditions. You may very well get away with doing it for your entire life without having any issue, but it's possible.
Incidentally, the penalty for suppressing that inductive spike (there is ALWAYS tradeoffs in electronics) is a slower release time of the relay (which may or may not be a good thing. A slower armature speed in theory could result in contact welding, if the relay is controlling an inductive load. Potter and Brumfield made a special relay intended for ambulance wig-wag lighting of headlight bulbs I don't remember the part number. It has to do with contact material migration from the movable contact to the fixed contact when switching heavy incandescent loads long term.
Another incidentally, some smart ass kid did a study for UPS and discovered that left turns are 13% more expensive than right turns overall, and laying out the routes in right hand spirals minimizing left turns saved some unbelievable number like 100 million per year company wide. The reason I mention it is because in a vehicle with incandescent lights and separate relays driving the turn signals, the left relays usually wear out faster than the right ones do. I've seen it a few times over the years.
Your mileage will undoubtedly vary. Ciao!
reply
Just tossing this out there. At 17: 40 or so you repeatedly install and remove the relay. I know this is an old video.
Instead of believing me, some day when you have the pico scope out, probe the 85 wire that grounds the relay coil. Get the wire end, not the relay end, and do the same thing.
The point is, the circuitry has inductive clamping/output protection/whatever you want to call it that is not being allowed to do it's job (because the relay is unplugged. Some relays are fitted with suppression diodes internally, this doesn't apply to what I am talking about.
When you do what you did, you may or may not see voltage spikes on the wire, that would depend on the driver they used and the efficacy of the suppression circuitry in that wire.
The overall point is that you are able to get away with doing that because of improvements in output protection that have occurred over the years with the availability of better parts and better design. With that said, that hasn't always been the case. Do what you did to an Allison transmission controller from the early days, and you would be buying a new ECU (back when they cost 3 grand) Same thing with probing the outputs with a test light instead of a meter. Too much load (incandescent test light) smokes the transistor. Not good enough inductive suppression smokes it too.
I guess what I am really trying to say is that by doing that, you are relying on the technology to protect you against what are essentially undefined conditions. You may very well get away with doing it for your entire life without having any issue, but it's possible.
Incidentally, the penalty for suppressing that inductive spike (there is ALWAYS tradeoffs in electronics) is a slower release time of the relay (which may or may not be a good thing. A slower armature speed in theory could result in contact welding, if the relay is controlling an inductive load. Potter and Brumfield made a special relay intended for ambulance wig-wag lighting of headlight bulbs I don't remember the part number. It has to do with contact material migration from the movable contact to the fixed contact when switching heavy incandescent loads long term.
Another incidentally, some smart ass kid did a study for UPS and discovered that left turns are 13% more expensive than right turns overall, and laying out the routes in right hand spirals minimizing left turns saved some unbelievable number like 100 million per year company wide. The reason I mention it is because in a vehicle with incandescent lights and separate relays driving the turn signals, the left relays usually wear out faster than the right ones do. I've seen it a few times over the years.
Your mileage will undoubtedly vary. Ciao!
reply
autos
Hey Eric, you referred to yourself as being lucky on finding that broken wire. Yet you said before you went in the trunk to find it, that that area is the area that's prone to breakage because of the movement. That isn't luck my friend, and if your to cotton picking humble to say that that is a demonstration of skill that comes with many years of hands on experience, than I will, because that is what it really is. You could have and did probably secretly know the problem, the moment the diagnosis led it to being a broken wire. The fact that even though we might have a good idea where to look first and you say its ok to visually inspect things but don't touch, so we can diagnose the circuit's integrity and find the actual cause without changing its condition, is an invaluable lesson to learn. Otherwise, comebacks are virtually inevitable without doing so. You as I've said before are not only a master but a diagnostic technician who is a step or two above the rest. Especially the Chevy dealers in not only your town, but across the country as well. I don't believe in reincarnation but I feel you would have lived before as a bloodhounds handler, tracking and out smarting the baddest criminals in the country, who always caught his man, or an ice cream shop owner, who was lactose intolerant! Lol. Take care as always and keep these unusual repair videos coming! Thier Great! Jpol. I'll comment right back with a link to a comedy skit from Cosby, called Tonsils! I know you'll enjoy it!
reply
Hey Eric, you referred to yourself as being lucky on finding that broken wire. Yet you said before you went in the trunk to find it, that that area is the area that's prone to breakage because of the movement. That isn't luck my friend, and if your to cotton picking humble to say that that is a demonstration of skill that comes with many years of hands on experience, than I will, because that is what it really is. You could have and did probably secretly know the problem, the moment the diagnosis led it to being a broken wire. The fact that even though we might have a good idea where to look first and you say its ok to visually inspect things but don't touch, so we can diagnose the circuit's integrity and find the actual cause without changing its condition, is an invaluable lesson to learn. Otherwise, comebacks are virtually inevitable without doing so. You as I've said before are not only a master but a diagnostic technician who is a step or two above the rest. Especially the Chevy dealers in not only your town, but across the country as well. I don't believe in reincarnation but I feel you would have lived before as a bloodhounds handler, tracking and out smarting the baddest criminals in the country, who always caught his man, or an ice cream shop owner, who was lactose intolerant! Lol. Take care as always and keep these unusual repair videos coming! Thier Great! Jpol. I'll comment right back with a link to a comedy skit from Cosby, called Tonsils! I know you'll enjoy it!
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Peter
A girlfriend I had asked me to look at her brothers 2000 Buick century, she brought it over and explained that the passenger side rear window didn't work, now this is the best part, her college educated brother and father brother is an engineer father is a pharmacist, so they thought the best way to diagnose it was to and I'm not, kidding, cut all the wires going to the main control switch on the drivers door about an eighth of an inch from the connector, so I did my best to solder all the wires back together, and I told her that I might have to go to the junkyard and get a new connector and leave more wire to work with, I went over to my friends at the time who owned a garage and one mechanic in particular was good at diagnosing electrical faults, he said check the wire that goes into the door because the wire unusually breaks inside the loom, I was sceptical but this guy has a ton of experience, I peeled back the loom and there it was, the broken wire, it just goes to show that experience is everything.
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A girlfriend I had asked me to look at her brothers 2000 Buick century, she brought it over and explained that the passenger side rear window didn't work, now this is the best part, her college educated brother and father brother is an engineer father is a pharmacist, so they thought the best way to diagnose it was to and I'm not, kidding, cut all the wires going to the main control switch on the drivers door about an eighth of an inch from the connector, so I did my best to solder all the wires back together, and I told her that I might have to go to the junkyard and get a new connector and leave more wire to work with, I went over to my friends at the time who owned a garage and one mechanic in particular was good at diagnosing electrical faults, he said check the wire that goes into the door because the wire unusually breaks inside the loom, I was sceptical but this guy has a ton of experience, I peeled back the loom and there it was, the broken wire, it just goes to show that experience is everything.
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MR
Great video and very informative! I have a 2007 Ext Cadillac. any chance that you can tell me why my backup/reverse lights stay on? I replaced the brake switch on the brake pedal. someone said the relay to the backup/reverse lights burned out in the ON position but I cant find the relay. someone else said that the relay to the backup/reverse lights is in that little BCM black box just left of the steering wheel? So I pulled the fuse cause it will run my battery down but doing that just drives me crazy!
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Great video and very informative! I have a 2007 Ext Cadillac. any chance that you can tell me why my backup/reverse lights stay on? I replaced the brake switch on the brake pedal. someone said the relay to the backup/reverse lights burned out in the ON position but I cant find the relay. someone else said that the relay to the backup/reverse lights is in that little BCM black box just left of the steering wheel? So I pulled the fuse cause it will run my battery down but doing that just drives me crazy!
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autos
As you say, a logical approach applies to many fields. In medicine we work through something called a differential diagnosis which is nothing more than a list of possibilities. We work through the list in a rational order depending on how common conditions are and on how dangerous they are and sometimes depending on how dangerous or expensive a test is. We even use the same word for this organized approach to the complaint.
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As you say, a logical approach applies to many fields. In medicine we work through something called a differential diagnosis which is nothing more than a list of possibilities. We work through the list in a rational order depending on how common conditions are and on how dangerous they are and sometimes depending on how dangerous or expensive a test is. We even use the same word for this organized approach to the complaint.
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mark
What a surprise. A GM product with crap wiring. Check into a battery powered soldering gun for 12 volt work like this. I've used one many times. I'm not sure what type of solder guns you've used but a good solder gun that is shaped like a gun with a trigger will give you heat in about 10 seconds unlike the pencil type that takes a few minutes.
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What a surprise. A GM product with crap wiring. Check into a battery powered soldering gun for 12 volt work like this. I've used one many times. I'm not sure what type of solder guns you've used but a good solder gun that is shaped like a gun with a trigger will give you heat in about 10 seconds unlike the pencil type that takes a few minutes.
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Peter
OK - I have spent 20 minutes Re-watching the video trying to spot the model number of that little butane Weller soldering iron / torch and I cannot see it. Eric skips over it too fast and the video description doesnt list that tool.
Does anybody know what the model number is?
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OK - I have spent 20 minutes Re-watching the video trying to spot the model number of that little butane Weller soldering iron / torch and I cannot see it. Eric skips over it too fast and the video description doesnt list that tool.
Does anybody know what the model number is?
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Jim
Eric, if your approach had been the exact opposite of what it was and you had found the problem at the other end, some jerk would say that's where he would have started. We all know about those folks. Arrogant aholes who don't have a lot of friends. Hey, I'll call you later. ;-)
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Eric, if your approach had been the exact opposite of what it was and you had found the problem at the other end, some jerk would say that's where he would have started. We all know about those folks. Arrogant aholes who don't have a lot of friends. Hey, I'll call you later. ;-)
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Chuck
Was pulled by the cops for no taillights. Didn't get a ticket. Turns out the wire connector soldered to the back side of the light socket had frayed off. Re-soldered it and good to go. Check the back side of the light housing to ensure the socket connections are good.
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Was pulled by the cops for no taillights. Didn't get a ticket. Turns out the wire connector soldered to the back side of the light socket had frayed off. Re-soldered it and good to go. Check the back side of the light housing to ensure the socket connections are good.
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autos
Hey Eric how goes it. Can you please put a link for that relay extender in the description. And where do you get the wire probe tips that clamp around a wire leaving just a little poke in the insulation. Two things I have to get to make life easier. Thanks. Jpol
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Hey Eric how goes it. Can you please put a link for that relay extender in the description. And where do you get the wire probe tips that clamp around a wire leaving just a little poke in the insulation. Two things I have to get to make life easier. Thanks. Jpol
reply
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