• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

TR6 New harness installed but have a purple problem

Share this page

nichola

nichola

Jedi Hopeful
Country flag
Offline
Finally finished installing a new wiring harness, but “finished” is definitely premature. As soon as battery was hooked up the fuse at purple wires would blow. Wasting a couple more fuses, I isolated it to the four bullet connector leading to the dimmer and flash to pass switch. If I unplugged the brown (picture attached) the fuse would no longer blow. The dimmer and flash to pass switch is new.

headlight switch works;
headlights work;
dimmer switch works when headlights are switched on;
flash to pass switch (pulling the stalk) does nothing;
horn button and (one) horn works;
I am not using the footwell and ign switch lamps, but I left those purple wires plugged into the bullet connector;
turn signals don’t work but that should be completely separate issue, powered by a green circuit.

I don’t get it. What could be causing that fuse to blow when the flash to pass switch is powered through that brown wire, even though the switch is not touched? I could live without it, but I’d like to start out with no mysteries.
10A81CF5-25BE-4B3D-9196-9EAB68B33CD0.jpeg
 
A puzzlement indeed! But since you're not using the footwell/key switch lamp circuit, you might try unplugging those (if you haven't already) to see if that's the culprit.

Keep us posted with any findings.

Mickey
 
When you say the headlights work OK, does that include the high beams? If so, it seems that it has to be in the switch somehow. You might try to isolate the problem--disconnect the wire to the switch (the one you arrowed on your figure) and confirm that you can measure a short to ground with an ohmmeter when you pull the flash switch. Then, disconnect the wire to the headlights, as close to the switch as possible, and see if you still get a short indication. If so, it has to be the switch.

I'm assuming that the fuse has the right value; it's easy to overlook.
 
Sarastro said:
When you say the headlights work OK, does that include the high beams? If so, it seems that it has to be in the switch somehow. You might try to isolate the problem--disconnect the wire to the switch (the one you arrowed on your figure) and confirm that you can measure a short to ground with an ohmmeter when you pull the flash switch. Then, disconnect the wire to the headlights, as close to the switch as possible, and see if you still get a short indication. If so, it has to be the switch.

I'm assuming that the fuse has the right value; it's easy to overlook.
Click to expand...
Thanks for replying Sarastro. The high beams and low beams both work when the headlights are switched on, by moving the dimmer up and down. But the flash to pass doesn't have any affect when the headlights are switched on.

That brown wire to the switch is disconnected because I'm running out of fuses! So, you suggest that I clip the ohmmeter to that brown wire and to a good ground and then pull the flash to pass switch, expecting to hear the tone and see a value of a few ohms resistance?
 
Going to leave the brown wire disconnected and live with it for now. Need to move on the fun stuff, like starting the engine first time in fifteen years.
 
I was suggesting putting the ohmmeter on the switch connection, with the brown wire disconnected and the switch off. You should see a short circuit when you pull the flash lever.

When you say that the flash has no effect with the headlights, on (it normally doesn't), is that with the brown wire connected? So, if the headlights are on you don't blow a fuse? But you do if they're off? If so, this sounds to me like it has to be some fault in the switch.
 
Sarastro said:
I was suggesting putting the ohmmeter on the switch connection, with the brown wire disconnected and the switch off. You should see a short circuit when you pull the flash lever.

When you say that the flash has no effect with the headlights, on (it normally doesn't), is that with the brown wire connected? So, if the headlights are on you don't blow a fuse? But you do if they're off? If so, this sounds to me like it has to be some fault in the switch.
Click to expand...
The brown wire cannot be connected because as soon as I hook up the battery it blows the fuse. So, the flash is not supposed to work with the headlights on... good to know. I tend to agree that it is the switch, so I'm going to yank it out and see if there's something obvious. Will report here, Thank you!
 
The flash to pass works when the headlights are on low beam ...at least mine does
 
I hope everyone knows that there are literally no correct harnesses on the market. The factory made
changes almost every year with poorly documented breaks. Since it is nearly impossible to supply
a "correct" harness that fits more than one year, all have a fault/inaccuracy built in.
Not once in my experience has a new harness not required some modification ,small or major.
This is helped by the correct diagram for your particular year ,if you have it. If not remember
Daunte. "Abandon here all hope......"
MD (mad dog)
 
mctriumph said:
I hope everyone knows that there are literally no correct harnesses on the market. The factory made
changes almost every year with poorly documented breaks. Since it is nearly impossible to supply
a "correct" harness that fits more than one year, all have a fault/inaccuracy built in.
Not once in my experience has a new harness not required some modification ,small or major.
This is helped by the correct diagram for your particular year ,if you have it. If not remember
Daunte. "Abandon here all hope......"
MD (mad dog)
Click to expand...
I thought my wiring harness was pretty good, my issues were all operator (me) error. Purchased it from Victoria British before they disappeared. This is my fourth wiring harness installation, the others were old Chevy trucks and those harnesses were from Rebel Wiring. It was really nice that each of Rebel's wires had the destination printed every six inches on the wire coverings, and their customer service was extraordinary. But, equipped with the wiring diagram and lots of patience, the TR6 harness worked out well for me. I will confess to a simplified installation with no heater, and no warning buzzers for seatbelts, etc., to deal with.

I think my issue with the dimmer/flash to pass is the switch or switch installation.

Love the quote... it has seemed appropriate from time to time with the TR6. And I haven't even progressed to the the BIG if... will it fire up (and not spring leaks everywhere).
 
The first thing you said " I got it from VB"says it all. Do NOT blame yourself. Blame is not a constructive
concept here. The defective circuit must be isolated/wired around. Welcome to H....
MD(Mad dog)
 
Back
Top