Jump to content

2000 gmc sierra 2500 7 pin trailer stop lamps will not work


jburk410

Recommended Posts

Posted

2000 gmc sierra 2500 7 pin trailer stop lamps will not work. so i hooked up a new 7 pin trailer socket and everything works fine except the actual stop lamps. i have running lights and blinkers. it was my understanding that the blinkers run the stop lamps but maybe i'm wrong. I've checked all the fuses and they are fine. the ground is good, there are no wires chaffed and i get a stop lamp signal for the third brake light. I've tried multiple trailers and even a test light, I'm starting to go crazy. Does anyone have any suggestions?

Posted

get a schematic and start from the beginning ,follow the circuit ,if it makes no sense to you ,,,,hit up a shop

Posted

You may already know this, but since you did not actually say it, I will, just to be sure you know this. The issue is not in the trailer, it is in the truck, and as suggested above, you need to locate the wiring diagram, and start checking for power in the brake light circuit. Start at the rear of the truck, and follow the harness to the front of the truck, checking for power at each connector that the wire passes through. I suggest starting from the rear simply due to the wiring being exposed to the environment for more than half its length. If you are a follower of Murphy's Law, start at the end you would not normally start from.

 

I have used this site a few times for reference. http://www.etrailer.com/faq-wiring.aspx. You can use it to determine which wire in the 7 pin connector does what.

Posted

2000 gmc sierra 2500 7 pin trailer stop lamps will not work. so i hooked up a new 7 pin trailer socket and everything works fine except the actual stop lamps. i have running lights and blinkers. it was my understanding that the blinkers run the stop lamps but maybe i'm wrong. I've checked all the fuses and they are fine. the ground is good, there are no wires chaffed and i get a stop lamp signal for the third brake light. I've tried multiple trailers and even a test light, I'm starting to go crazy. Does anyone have any suggestions?

You are correct that the turn signals and brake signals use the same wires (yellow & dark green). Since the turn signals work properly that pretty much rules out a wire or ground being the issue. If the truck brake lights are working you probably have an issue w/ the turn signal/hazard switch or possibly the wiring going to it. schematics.pdf

trailer.pdf

schematics.pdf

trailer.pdf

schematics.pdf

trailer.pdf

schematics.pdf

trailer.pdf

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Forum Statistics

    250.4k
    Total Topics
    2.7m
    Total Posts
  • Member Statistics

    342,759
    Total Members
    8,960
    Most Online
    DM22
    Newest Member
    DM22
    Joined
  • Who's Online   5 Members, 1 Anonymous, 1,741 Guests (See full list)

  • Latest Articles

  • Posts

    • Did have to make 1 modification because of the WeatherTech rear mud flaps and that was needing 3 longer screws than what came with the install package. 😄
    • Picked up the liners yesterday. Installed passenger side WITHOUT any modifications. All mounting holes lined up perfectly. Rain is interfering today with drivers side. Very Happy! Will add pics when finished
    • As a matter of amusement I’ll leave this conversation with this. Do you beat the government average fuel estimate? Statistics are a guide to me. Not a rule. Someone once said I have to have the last word. If true and possible may be. I’ll blame that on working in a family business.
    • That is a fair point, and I agree that trying to log “everything in the truck” would be the wrong direction.   There are a lot of modules and a lot of traffic. If the product became a full-truck datalogger, the amount of data would get huge very quickly, and most owners would never use it.   I think the first useful version would need to be narrow: - powertrain-side event evidence - selected high-value parameters - communication / voltage / reset events - pre/post event window - short report first, raw log only as backup   One distinction I should make is between active OBD/PID polling and passive bus capture. If you are polling PIDs through OBD, then yes: the more parameters you request, the lower the effective sample rate becomes, and you are adding diagnostic traffic to a vehicle that is already busy running itself. With passive CAN capture, the recorder is not asking all the modules for data. It is listening to traffic that is already on the bus. So it does not consume vehicle bus bandwidth in the same way that a scan tool polling hundreds of PIDs would. But your point still applies in a different way.   Even if passive capture does not add bus traffic, the recorder still has limits: - processing rate - storage rate - timestamp accuracy - decoder workload - event filtering - report size - user attention span   So the answer cannot be “log everything and let the user figure it out.” The product would need to store enough raw evidence to be useful, but only decode, graph, and present the important parts around the event.   A practical report should probably show: - what triggered the capture - how much pre/post data was preserved - which selected parameters changed - how those values compared to baseline - whether the same pattern happened before - whether any voltage, reset, bus-off, lost-message, or communication fault occurred - selected graphs around the event - raw data only as supporting evidence   So I agree with you. More data is not automatically better. The real product is the reduction from raw data into a useful event report.
    • That makes sense, and I agree with most of that.   I think the product would need both: 1. a default powertrain template, so it is useful out of the box; 2. user-selected priority parameters, so the owner or shop can choose what they want to see first.   Different users are going to care about different things. One owner may care about oil pressure and voltage. Another may care about misfire trend, AFM/DFM behavior, or U-codes. A shop may want communication events and repeatability first. Your baseline point is probably the most important one. Raw data is not very useful unless the report can show what normal looked like for that vehicle under similar conditions.   The way I would think about it is: - start with a basic known-good baseline - learn normal behavior for that specific vehicle over time - allow the event to be overlaid against baseline - show whether the event was a one-time spike or a repeatable pattern - provide a simple severity level, but with clear limits on what that severity means   For example, early severity could be something like: - Info: event captured, no obvious abnormal pattern - Watch: value moved outside baseline, but not repeated - Warning: repeatable abnormal pattern under similar conditions - Critical: communication loss, voltage drop, bus-off, reset, or severe repeated event   I would not want the first version to say “replace this part.” That would be overclaiming unless there is repair-confirmed data behind it. It would be more honest to say “this pattern deserves inspection.”   On the OBD port question, I think OBD absolutely has a role. OBD is probably the right place for: - DTCs - freeze frame - VIN - calibration information - normal scan-tool parameters - Mode 6 / enhanced diagnostic data if available The reason I am still looking at an ECM-side recorder is that the failure may happen before anyone connects a scan tool. If the owner plugs in a scanner after the event, the pre-event evidence may already be gone unless the ECU happened to save it. So I do not see this as “OBD versus ECM-side.” I see it more like: - ECM-side recorder: always armed, rolling buffer, event evidence - OBD/DLC companion: DTCs, freeze frame, VIN, calibration, normal scan data - phone/cloud: status, notes, upload, report generation, notifications   I agree that phone connection and push notifications would be useful. I just would not want the phone or cloud connection to be required for capture. The recorder should save the event locally even if the phone is not connected. The phone should help with event marking, download, notes, upload, alerts, and report viewing.   For a default GM V8 event report, would this list make sense? - RPM - calculated load / MAP - throttle position - vehicle speed - gear / torque converter state if available - coolant temperature - oil pressure - oil temperature if available - battery voltage - commanded AFM/DFM state if available - actual AFM/DFM state if available - misfire counters / roughness by cylinder if available - fuel trims - relevant U-codes / communication events - bus-off / lost periodic message / module reset / voltage drop events Which of those would you remove, and what would you add?
  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...