Passenger low beam dim & blinker light frozen on

Hi guys,

Tonight I noticed that the passenger Low Beam is dim (barely on), and the passenger blinker stays on (illuminated orange) if blinker stalk is in it’s neutral position.

If i turn on the blinker left or right, the blinker works as it should, although the passenger side blinker is also very dim and struggles to light up properly upon “blink”. The driver’s side works fine.

Last summer I replaced the hazard switch with a new unit along with a new plastic rocker lever, which fixed a different problem I was having (the low beam would “blink” along with the blinker). This issue is resolved… but this new one is now plaguing me.

What could be causing this odd electrical gremlin?

How was that issue resolved, Tyler - after all it is still the same items involved…?

What about high beam, and indeed; is the problem present with the light switch ‘off’?

There is no obvious ‘connection’ between the headlamps and direction indicators. Generally; whenever an electric problem is completely incomprehensible - old wisdom decrees that a ground fault is involved…:slight_smile:

I suggest you check/change the headlamp bulb - an internal fault may be involved. And test blinker functions with head bulb out - light switch ‘on’ and ‘off’. Also check head lamp and blinker lamp grounds. The direction indicator may somehow be powered from the low beam bulb - dimming both, using some obscure path to ground…

…or whatever; symptoms make no immediate sense - but did you work on the wiring previously…?

xj6 85 Sov Europe (UK/NZ)

Check your grounds.
It’s bizarre though, the lights and the indicators are two completely different circuits.

If it’s a Federal car then you have a double filament light bulb for front indicators and pilot lights.
Maybe something is wrong there ?

I dont think my car is a federal - pretty sure it was just a base model 84 XJ6.

As for the old issue last summer, when I would turn on the blinker, the low beam would actually dim along with the blinker and the blinker light would ALWAYS be illuminated , no matter what position the turn signal stalk was in. That issue went away… and now I have this one instead.

The bulb failure light is on in the dash… which I believe, if memory serves correct, that there is an imbalance in the circuit somewhere. How and why and where that is… is up to discovery.

Where are the ground points for the headlamps? Is there an electrical schematic online that I could follow? I used to have a PDF on an old laptop…but it got stolen, sadly.

It looks like there is but one ground for the entire blinker circuit - where that is, I have no idea:

As for the headlights… im not sure how to read this diagram - why are there 8? headlights?

Federal: 5 inch main beams. Catalysts. Lambda feedback. Air injection. ‚Federal‘ tag on RH fender. Position lights. 5mph ‚bench‘ bumpers.

The headlights ground somewhere, maybe where the two reinforcement struts are anchored above the shock absorber nut?
The Blinkers ground at the body somewhere, you might have to do some dismantling. If they ground at the same spot, but that spot provides no ground, it would still need to ground through a positive wire?

There should be 4 main, 2 low, 2 fog if fitted, 2 city or position lights forward. The bulb failure units are only for the rear I think and you got the principle correct.
Whatever that is. If you follow all the wires you’ll sort it out :slightly_smiling_face:

The bulbs, including the blinker bulbs, are separately grounded, Tyler. Either by wires at the bulb holder, or to the reflectors, which are then grounded, either by the mounting screws or wires. But ground wires might terminate at the same grounding point - which may explain anomalies…

You just have to access the respective components to check - starting with the malfunctioning ones. Ground wires are usually plain black - but generally; the wiring diagrams do not show physical routing of wires…

With the bulb failure light lit; one bulb is not drawing the correct current. The first step is invariably a visual inspection of lamps - and change the bulb in the offending lamp. In this case the low beam passenger (‘right’ hand?) side.

The direction indicator circuit has two ‘grounds’; one for the flasher relay directly to ground. And one, ‘indirect ground’, through the stalk switch which powers the selected indicator side - while using the unused external lamps to ground the dash indicator repeater lamps as appropriate…

The dash direction repeater light has two diodes to prevent current backfeed - failed diodes may wrongly light the repeater(s). The indicator circuitry is rather intricate - but you likely have two separate faults…

To further clarifying symptoms; is there any anomalies in the direction indicators with the light switch ‘off’ - or indeed with the low beam bulb, or the passenger (‘right’?) fuse removed. Both prevents crossfeeding indicator bulb from the low beam circuit…

Also; what about the rear indicator lamps - do they mirror the font ones. And, indeed, what about high beams…?

xj6 85 Sov Europe (UK/NZ)

Well, I checked the headlight fuse block, everything seemed OK there. I checked the grounds, unscrewed them (what I thought to be the headlight grounds, anyways) and reinstalled them.

The issue remains - the rear tail lights/blinkers operate as they should - neither is more dim than the other. It is just the passenger side low beam (the one that is part of the fender, rather than the hood) as well as the passenger side blinker. If I turn the high beams on, the issue continues.

I didn’t pull out the headlamp or bulbs - it was too darn hot to keep working outside and the internet out in the country is spotty at best. That will be my next issue to tackle.

I did notice that under the headlamp fuse block, there was a RED/WHITE wire which wasn’t connected to anything - I am assuming this went to the old electric fan clutch - the headlamp wiring schematic did not show a RED/WHITE wire from the fuses… but also the schematic left off fuse 1 (what a dumb diagram), so I assume that this is what that wire is for.

There is a White/Red wire (not Red/White as you mentioned) located near the Headlamp Fuse Box that is for the Low Coolant Sensor on the brown coolant header tank. If this is disconnected then the warning system that provides the alert that your coolant level is low is not functioning. I consider this a pretty important warning system and I highly recommend that you see if this is what the wire is and reconnect it.

I don’t know what wiring diagrams you are using but the white Maintenance Handbook shows what fuses are in the Headlamp Fuse Box. The #1 fuse is for the auxiliary cooling fan and noted in the Maintenance Handbook and in Figure 16.1 of the S57 Electrical Guide.

If I were you I would swap out any inoperative bulbs with known good ones to see if you have bad bulbs or a system problem.


I second Paul’s proposal, Tyler; with the bulb failure light lit and the problem present in both high and low beams - changing the headlamp bulb is a first step. It’s a relevant and uncomplicated test - also testing direction indicators and dash repeaters with the bulb out…

Car electrics are intricate, but for current to flow; both a power feed and a ground is required. A feed may be illicit due to some short - but a ground may indeed be provided by any unpowered powered wire. as David implies…

In car electrics; all wire connections ultimately wind up to ground - sometimes through very devious routes…:slight_smile:

xj6 85 Sov Europe (UK/NZ)

Got a chance to work on the bulb issue again this weekend - indeed the blinker light on the passenger side is always On, if the blinker stalk is in the “neutral” position. It blinks as it should when the stalk is in the up (right side) position, and the down (left side) position blinks as it should when on.

The headlight is dim, which I am going to replace today. Perhaps that will be fixed. When I turn on the brights, all the lights except the passenger side low beam are bright.

This is obviously a ground problem. How has it gone for months?

Just haven’t had a chance to work on it- the car is usually stored out in the country, so I only get to work on it when I’m visiting my in laws.

I have no idea where else I could look for the ground issue - do you have an idea?

What happens to the headlights when the stalked is out of ‘neutral’, Tyler - and what happens to the blinker light with the light switch ‘off’?

You may have two different faults, have you changed the headlamp bulb…?

xj6 85 Sov Europe (UK/NZ)

Haven’t changed the bulb yet although I do have a spare waiting… when the stalk is out of neutral blinking for the passenger side front turn signal, it blinks as it should - same when I switch the blinker to the other direction. When it’s in neutral, the passenger front blinker just stays illuminated.

The sockets for the headlights and blinkers. They’re supposed to be grounded; if it’s not obvious how, add a ground wire to each.

Changing the bulb is a first step, Tyler - with dual filament bulbs, odd things sometimes happen…:slight_smile:

The headlamps and flashers are fed by different sources; the former from the light switch - independent of the ign key position. The latter is fed from the ign key out of ‘off’.

One question is if the flasher is affected/powered by the headlamp switched on - ie flasher lit with headlamps on, and key switched off? Secondly, with the headlamps ‘on’ - is the flasher lit with ign ‘on’, and key ‘off’?

Further; when the flasher is used ‘left’ or ‘right’ with lights on - is the headlamp steady (but weak), or does it ‘blink’ in step with the flasher?

Also; is the ‘passenger’ headlamp weak both in ‘high’ and ‘low’ beam. Somewhat intricate; can you see if both bulb filaments (‘outer’ lamp ‘left’) are lit in ‘high’ beam?

The point of this is verify if you have two different and independent faults - or somehow hang out together…

Have you also checked if both the front and rear blinkers are ‘on’ together with the indicator stalk is in neutral? Basically; ‘front’ and ‘rear’ indicators lamps are operated in tandem, side to side - theoretically, they cannot differ by switch operation…

As an aside; do the dash indicator repeaters work as they should - not lit with the switch in neutral…?

xj6 85 Sov Europe (UK/NZ)