Scamp wiring conundrum

[Lockman]

So the left side has a short in the line some where, Check even with the black wire disconnected. If so, a possible cause is the wiring harness is rubbing on the chassis somewhere. Maybe close by in the hitch area? Follow it to where it enters the Scamp?


Keep us informed.

[redbarron55]

Electrical terminology is often misused.
When the term short is used to me it means that a wire is unintentionally connected to ground because of a failure of insulation (or perhaps to another wire for the same reason).
A short to ground causes fuses to blow and wires to overheat and insulation melt due to the heat.
A wire that is open means that current is not being passed to the load and basically nothing happens.

I think you have an open circuit (noting not blowing fuses and no smoke from burning insulation).

I see in the pictures that you have the Scotch lock connectors that are not noted for extreme reliability.

When measuring for "shorts" with a meter a light bulb will read very close to "0" ohms as the filament is basically one of those shorts that gets hot and glows.
The filament heats up and the resistance increases dramatically and thus does not draw excessive current after a quick surge to heat things up.

I would look at any of the Scotch Lock connectors I could get to and sharpen the probe on your meter to penetrate the insulation or better still perhaps just use a straight pin to do it and probe to the copper conductor as you work your way back.
Since one of the bulbs works and they share a common ground the problem is probably not in that part of the circuit.
A wire is not likely to have separated within it's insulation, but it is possible.
Most likely are those pesky splices between the connector and the bulb.
Use the pin and meter with the wire energized and find out where you have the interruption.
Step by step wins the day.
Find any place you can get to the wire and poke that pin in to check for voltage.
I would not worry particularly about the pinprick through the insulation.
The first place to check is right before the wire goes to the socket as often these taillight sockets are (Redacted) up.

[nigeleccleston]

I finally saw my right turn signal flash!
I bypassed the existing supply wire(s) by splicing a wire from the gReen wire up by the 4-pin and ran it direct to the black wire that connects to the turn/brake filament of the 1157 bulb.
So there is a fault somewhere along that supply line. I can see that a PO cut off the original 6-pin connector and spliced a 4-pin. That is the most likely spot, and I hope that's the problem, rather than something with the brown wire inside the Scamp. I should be able to tell by repeating Lockman Jack's resistance comparison at a point between the Scamp and the 4-pin splice.
Now if it would just stop raining...
There is a ton of good troubleshooting information in the posts and messages I have received on this topic. I may try to put it all in some systematic order for future reference. What a blessing this community is!

[John in Michigan]

Nigel that's great. When checking that splice near the 4-pin connector (and any other splices) I would agree with redbarron that the scotch-lok connectors are notoriously unreliable. In those cases, I would replace the scotch-lok connectors with crimp splice connectors using a good quality crimping tool.

[Lockman]

Good work Nigel, I am sure you will find the problem at that splice, most likely corrosion if its outside the Scamp. Glad it worked out.



If you get the time post some pictures.


Jack