My front right marker light and parking light don't work. Nor does the turn signal on the front right. I cleaned the ground as that is common to the circuits and i think it's now good (headlights working). I also have power at fuse #15 which feeds both those bulbs. What I don't understand is this: If my parking lights are on - how does the turn signal circuit now turn on and off that bulb that the parking light circuit is steadily powering?

 

It doesn't. Not on mine, at least.

The bulb is dual filament, bright and not-so-bright (turn signal and park lamp, respectively)

If the park lamp is 'on' that filament remains powered-up even with the turn signal in use. If gives a bright-dim alternating effect.

If the park lamp is 'off' when the turn signal is used only the high intensity filament will glow .....so it gives an on-off effect.

Cheers
DD

 

Alright, that certainly makes sense.
Now I'm looking for a short or a break somewhere. I guess the most likely place for a problem would be at one of the bulb connections rather than the wire although I suppose it could be shorted against the body somewhere. The fact that both marker and turn are out really suggests the ground but it looks ok. If I take out the bulbs on the park light front and back and the marker, I believe I should get no conductivity between the fuse and ground, correct? Otherwise there is a short. If I weren't below freezing out I'd work on it for more than 20 minutes at a time.

 

I have 12 volts at my side marker socket according to my meter but when I put a new bulb in it won't light. Cleaned up the socket with a dremel but still nothing.

 

look behind the fender for a black cable connected to the rear of the Side Marker lamp.

The red wire goes into the lamp,

the black wire is connected to the lamp's housing with a "bullet" type of connector, and this bullet is pushed inside a "springy" rolled "J" which sometimes breaks.

if broken, you can solder it to the remnant of the "J" leg, or flatten the "J" and use a female spade connector soldered to the black wire.

 

Ok, thanks! Makes sense the problem is in the bulb sockets. I considered buying a new marker socket but I think the original is fixable. One marker light bulb turned to dust when I was handling it so I bought all new ones. I don't know why I suddenly have voltage to the socket but these things only add to the cars charm.

 

in my experience, the bulb itself is the problem, not the socket. The bulb does not seem to be a perfect fit for the socket.

I am talking about the STATIC SIDE MARKER LAMPS, by the way, those lamps were used in MG-B and MG-C of the same period. Identical. British Leyland.

The Bumper's lamp is basically trouble free.

 

It does seem to be a sloppy fit. I have voltage and it looks clean but the bulb won't light.
Well it has voltage until I put the bulb in for the turn signal (which doesn't work either) and then the voltage at the marker disappears. I'm going to have to take these sockets apart and analyze them.

 

try turning the parking lights ON, then go to the Side Marker Lamp, remove the lens, and try pushing the bulb IN until it comes on. I have had the same problem. You might have to sacrifice a bulb, it might break if yoiu force it in too hard.

As to the Turn Signal Indicator in the Tachometer or the Speedometer, that is a problem at the switch itself, ASSUMING all the exterior Turn Signals blink. even if the Dash Indicator doesn't.

the inner contacts wear out. It can be repaired by removing the switch, opening it and finding out what is causing it, usually one of the Brass contacts inside.

 

I'll try that. I think it's funny you blame it on the bulb not the socket - a true Jaguar fan..

 

I should remember since I've repaired more side marker lamps than you can shake a stick at, but.....I'm having a bit of brain fade it seems.

I recall that these are spring loaded sockets. I seem to remember taking them apart and stretching the spring so it provides more tension....thus improving the sloppy fit of the bulb in the socket...and thus the little bulb pegs firmly contact the wall of the socket for grounding.

A little smear of vaseline on the sides of the bulb helps keep corrosion at bay

The little ground hoop-tab-thingy mentioned by Jose is the biggest culprit, IMO.

I usually defend Lucas stuff because, too often, it gets an unjust amount of criticism. However, these non-sealed electrics in a location totally exposed to the weather are really bad !

Cheers
DD

 

So far, those lamps work just fine on my car. Lucky me.


In a past critter, I had a similar issue with a tail lamp. The contact point on the lamp was a blob of solder. Similar to the blob on the end of the bulb. A careful look seemed to indicate the blob in the socket was well worn?? I soldered on some more material ugh, too much, . so, I trimmed it til it accepted the bulb with snug fit. Lit right up, the way it should....


Carl

 

I always try to report closure to my forum problems. I traced the front parking light failure to a failed butt splice to the wire just behind the bumper where the wires go into the body. I have about an inch or two of wire to work with to make a new splice. The turn signal on this socket did not work either and I found under the hood that the green/white wire coming from the switch ended there at one of those white double bullet connectors. (why would there be a double connector there?)
Diagnosis done but repair will have to be another day as it's getting late and the Super Bowl is on. I also plan to replace the socket with this one that I found cheaply on Amazon. Fits the reflector perfectly - even locks in with the O-ring:

 

totally agree these lamps are bad.

also agree that if the Red "hot" wire, (the wire that goes into the lamp and contacts the bulb), is not "out" enough, (the spring has become unsprung??) then the bulb will not make enough contact.

That's why I said to push that bulb in even if it breaks, chances are you can make it turn ON before it breaks, then you will know the red wire contact is too deep into the socket.

 

It's also impossible to get your fingers around the bulb to push into that space and turn it. I'm using a piece of fuel line to hold the bulb and push it in.

 

Could you send the Amazon link for the 1157 bulb holders?

 

No problemo.
I'd like to put it in the Jag Lovers parts interchange but can't figure it out what with their updating to a new site and all.

 

Jose, You said that if the indicators in the Speedo/Tach do not blink and everything else works, then th problem is in the switch itself. Can this be fixed without replacing the switch?

 

you have to dismantle the switch from the steering column, and removing the steering wheel with the wheels straifght ahead , using the Service Manual steps.

once you have the switch out, you need to drill the rivets out, and separate the two halves of the switch carefully, springs will jump out never to be found.

Then you can analize the brass contacts and fix them, add dielectric grease, etc.

it is delicate surgery but it can be repaired. I've done it to both the wiper switch and the turn signal switch.

 

Thank you Jose, If my troubleshooting yields no results, I'll tackle the switch. Appreciate your guidance.