• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)

TR2/3/3A TR3 Right Brake Light Issue


Jedi Hopeful
Without the running lights on both brake lights work when I apply the brakes.

Now here is the strange part, when the head lights are on and the brake is applied the left light and brake light work fine but the right light goes totally dark.

Both the brake light and the running light seem to be a little dimmer on the right. I have switched the bulbs and the right light still has the issue.

Any ideas?


Great Pumpkin
Country flag
If 1 side is dimmer than the other I think that usually means grounds.


Great Pumpkin - R.I.P
Now here is the strange part, when the head lights are on and the brake is applied the left light and brake light work fine but the right light goes totally dark.
Classic symptom of a bad ground.
When either set of lights are on, the right lamp grounds through the other system's other bulb(s) (which also explains why it's a bit dimmer). But with both sets on, there is no current path through either right filament, so the right bulb goes out.

The original ground is through the 2 screws that hold the fixture, and the clip nuts that the screws go into. Usual problem is corrosion (or paint if recently painted) between the clips and the body, but of course could be anywhere along the path.

My suggestion is to add a ground wire to all of the rear lamps. They have sockets for bullet connectors already, so all you have to do is make up the wire(s). Mine daisy-chains across the back, then runs forward to one of the gas tank bolts. Chances are, the other lights will get brighter as well.


Jedi Hopeful
Perfect, it turned out the clips on the trunk side for the mounting screws were rusted and loose. I replaced the clips and it all works now.


Geo Hahn

Country flag
Bad grounds produce some truly squirrely results. I had a bad ground on one headlamp that caused the headlamp not to work and the high beam indicator to be on whether hi beams or low beams were selected.


Great Pumpkin
Country flag
Electrons are an opportunistic lot. Path of least resistance every time. Whether that means goin' thru the high-beam indicator lamp, or the filament of the left rear running light. Squirrely, indeed.
Similar threads
Thread starter Title Forum Replies Date
W TR2/3/3A '56 TR3 St 15000+ should have disc brakes... Right? Triumph 33
Lbp TR2/3/3A Are These the Right Tires for a TR3? Triumph 1
rckuhlman TR2/3/3A TR3 Castle Nut on Right Rear Axle Triumph 3
B TR2/3/3A TR3. Would you put it back to right hand drive? Triumph 11
Got_All_4 TR2/3/3A TR3 leans too much to the right Triumph 10
Got_All_4 TR2/3/3A Tr3 leaning to the right Triumph 6
J TR2/3/3A TR3 right turn signal not working Triumph 15
J TR2/3/3A What size speedi-sleeve needed for pinion seal on a TR3? Triumph 0
T For Sale Free - Body Jig for TR3/TR3A Triumph Classifieds 0
J TR2/3/3A TR3 engine cylinder top clearance Triumph 22
BillyB62 TR2/3/3A Looking for the Owner of a TR3 Triumph 5
Pool Dad 1960 TR3 engine serial number Triumph 14
T TR2/3/3A TR3 coolant hoses Triumph 2
T TR2/3/3A Has anyone designed a hand brake warning light for the TR3? Triumph 3
J TR2/3/3A "TR3" painted on the engine block Triumph 13
J TR2/3/3A TR3 Rear seat Triumph 11
D Socket for TR3 Gear box drain plug Restoration & Tools 6
J TR2/3/3A TR3 gas tank mystery Triumph 5
T Wanted Wanted - 1956 TR3 Crankshaft Triumph Classifieds 0
jfarris TR2/3/3A Venture into the "dark side," Miata seats in a TR3 Triumph 2
T TR2/3/3A Question on old radio from my TR3 Triumph 9
T TR2/3/3A tr3 front carpet replacement Triumph 5
T TR2/3/3A Should there be a body ground strap to battery on TR3 Triumph 7
G For Sale: Triumph TR2, TR3, TR3A Sheet Metal Body Parts – Front Apron (valence) with grille, Bonnet (hood), Doors, Boot (trunk) Deck Lid Triumph Classifieds 3
G For Sale: Triumph TR2, TR3, TR3A, TR3B Factory Steel Hardtop, New Rear window, Partial Bracket Set Triumph Classifieds 2
A TR2/3/3A Early TR3 starter (bomb style) bushings sizes Triumph 5
T For Sale TR2 - TR3 Gas Cap for sale Triumph Classifieds 1
B TR2/3/3A TR3 Hard Top Triumph 2
D TR2/3/3A TR3 throttle linkage bell crank. Triumph 13
M TR2/3/3A Defective master cylinders Tr3 Triumph 13
BarryO TR2/3/3A setting up a TR3 clutch slave Triumph 5
M master cylinder brake/clutch Tr3 Triumph Classifieds 6
C TR2/3/3A TR3 Gearbox Problem Triumph 10
Tr3aguy TR2/3/3A Started a Car revival channel for the TR3 Triumph 12
J TR2/3/3A Any advice for new floor install on my TR3? Triumph 9
D 1957 Triumph Tr3 Triumph Classifieds 2
P TR2/3/3A tr3 side curtains Triumph 4
banjojambo Triumph tr3 vertical link wobble Triumph 2
S TR2/3/3A purchased a box of tr3 parts this weekend, Triumph 1
C TR2/3/3A TR3 close by Triumph 2
D TR2/3/3A Tr3 horn testing and wiring Triumph 8
J For Sale Triumph TR2 TR3 TR3A New Moss Motors Black Karvel Style Carpet Kit Triumph Classifieds 0
B TR2/3/3A TR3 sag to the left [port sag] Triumph 10
K For Sale Triumph TR3 Bullnose Starter Triumph Classifieds 0
K For Sale TR3 rear rebound brackets Triumph Classifieds 0
K For Sale TR3 Radiator Guard Triumph Classifieds 0
S TR2/3/3A TR3 has me stumped, it runs then dies over and over and the exhaust system was pulled Triumph 9
D TR2/3/3A TR3 Headlamp Rings Triumph 8
O For Sale New Member from NJ 1960 TR3 Triumph Classifieds 1

Similar threads