DeanoH
12th May 2012, 09:40 PM
My recently purchased 1995 Landrover Defender 130 had the 'unique' property of having no working lights, none at all. Head, side, brakes, reverse, blinkers, instrument, reverse etc......................nothing, not a one.
This post is about fixing the head, side, tail and instrument lights in this model Defender. I don't reckon there'll be much difference in similiar Defender models but I can't say for sure.
What is really handy is a copy of the vehicles circuit diagram, though basic fault finding can be done without it. ( A lot easier with it though).
Pages 43.3 & 43.4 refer. (though is only 32 pages in total).
For this sort of testing/fault finding it's best to use a test lamp NOT a multimeter. :)
A copy of a the '97 model year' Defender circuit diagrams can be found here.
http://www.legionlandrover.com/manuales/electrical%20schemes%20-%20defender%20300%20tdi.pdf
This manual, though for a 1997 model is the same, so far, for my 1995 model.
Lighting circuit description.
Lighting power is fed from the battery via a fuse panel mounted in the engine compartment next to the 'heater box'.
https://www.aulro.com/afvb/images/imported/2012/05/873.jpg
Link 1 powers the lighting. It's the one on the left (30A) and is at the rear of the fuse box closest to the firewall. Link 2 feeds the ignition switch, also important for lighting (as ignition must be on for the headlights to work), Link 3 (60A) does the glow plugs and Link 4 feeds the aircon (20A in photo but should be 30A).
Note. These large fuses are referred to as links (as in fusable links) and shouldn't be confused with the fuses in the vehicles cabin which will be referred to as FUSES.:)
Link 1 feeds the main light switch (LHS of steering column) which is a three position switch. Pos 0 (closest to driver) is off, pos 1 is park or side lights, tail and instrument lights and pos 2 is headlights.
Note. Ignition must be on for headlights to work.
The main fuse panel is in the cabin and looks like this.
https://www.aulro.com/afvb/images/imported/2012/05/874.jpg
There are 20 fuses in the fuse box. They number 1-10 (left to right) in the upper row and 11-20 in the lower row.
Note. In the above picture Fuses 1, 10 & 20 are not installed.
From the main light switch [SWITCH-LIGHTING (S100) on the circuit diagram] the 1st switch position (park) feeds power (from brown wire) via the red wire to fuses 15 & 16. Fuse 15 (5A) feeds the front LH side light and the rear LH tail lamp. Both these lamps should be 5 watt. Fuse 16 (5A) feeds the front RH side lamp and the rear RH tail lamp (both 5 watt). Fuse 16 ALSO feeds the instrument panel side lamp warning light.
If you don't get this far you've probably got a blown fuse or a crook light switch, probably the light switch, but more on this later.
Things get a bit trickier when the headlights are switched on. The above circuit remains activated when the headlights are switched on.
Power is fed from the main light switch (now on pos 2) via the blue wire to the RELAY-HEADLAMP (R123). This relay is mounted underneath the fuse panel and is the relay on the LEFT (yellow in picture but can be any colour).
This relays function is to ensure the headlights can only be on when the ignition is turned on. It is not a headlamp relay in the conventional sense in that it DOES NOT relieve the main light switch of the headlamp current load.
If you suspect that this relay may be faulty, or that it provides a 'feature' you don't desire or that you don't want to have the ignition turned on whilst fault finding it can easily be disabled/bypassed this way.
https://www.aulro.com/afvb/images/imported/2012/05/875.jpg
This relay operates whenever the ignition is on and directs the headlamp power to the columm mounted dip switch [SWITCH-COLUMN (S123)], (blue wire in blue/red out) to fuses 11 &12 via RELAY-DIM DIP (R126) on the circuit diagram.
On my basic defender the RELAY-DIM DIP (R126) does not exist. It appears to be a light dimming timer relay that may be provided on more 'upmarket' or later models. Never the less its plug in base is hidden up behind the dash. On my Defender a 'dummy' relay was provided. This dummy relay provides a 'short circuit' connection between contacts C048-8 and C048-2 (on the circuit) which are the two blue/red wires.
https://www.aulro.com/afvb/images/imported/2012/05/876.jpg
This relay (red box in picture) is hidden up behind the instrument panel and (in my case) is nothing more than an expensive short circuit connection between the two blue/red wires. In my case this was faulty. The connectors between the red 'can' and base had heated and melted the plastic resulting in a poor connection. I cut the blue/red wires from the base and soldered them together in a 'proper' short circuit to fix the problem.
Again, to simplify fault finding or to remove an unwanted feature this relay/short circuit module can be removed and a link placed between the two blue/red wires to simplify things.
From here the blue/red wires feed via Fuses 11 & 12 to headlamp RH and headlamp LH respectively.
When high beam is selected the output from the columm mounted dip switch SWITCH-COLUMN (S123) is directed through the blue/white wire to the high beam warning lamp and via Fuse 13 & 14 to the LH & RH high beam headlamps respectively.
Headlight Switch
As there are no headlight relays the full lighting current load is fed through this headlight switch. Total load is around 12 Amps, and this is for the standard 55W/60W headlights. Don't even think about higher wattage globes, the system was marginal when new for the original globes.
The headlight switch is the weak link in the lighting chain, essentially it is a 'made to a price' component that will fail.
https://www.aulro.com/afvb/images/imported/2012/05/877.jpg
https://www.aulro.com/afvb/images/imported/2012/05/878.jpg
The switch contacts are fitted in a piece of white plastic. If (when) the contacts heat up with the lighting current flow the plastic softens and the copper contacts 'sink' into the plastic and become a poor connection due to less contact tension and/or melted plastic on the contact surface(s). As the copper contact 'regresses' into the plastic its riveted connection on the bottom side of the plastic plate also loses tension compounding the poor connection problem.
A new switch costs somewhere between $20 (UK) and $80 (Aus) and will ultimately fail again anyway unless something else is done.
What I've done (above) is push the contacts back through the plastic and solder the contact connection/rivet on the underside. The heat from the soldering iron softened the plastic and made this easier to do and has hopefully now 'set' the contacts back in their original position. A close look at the first switch picture shows a gap between the plastic and the copper contact, this gap could be filled with some sort of glue/epoxy if you were keen enough. The rivet/contact plate connection is clear on the blue wire (headlight) connection on the second light switch photo.
The overall goal is to decrease switch contact 'stress' by installing headlight relays which decrease the switching current. This also increases the lighting efficiency as there is lesss voltage drop getting the power to the headlights.
https://www.aulro.com/afvb/images/imported/2012/05/879.jpg
This picture shows a high beam and a low beam relay on the passenger side, duplicated on the drivers side. (There is an extra red power cable in case I install driving lights later).
Switching current on the lighting circuit has been reduced from around 12 Amps to less than 2 Amps.
Total cost was less than the cost of a new light switch, though I did have the cable lying around.
I ran the power cable to the relays from the back of the alternator and used the existing earth return. Total voltage drop is 0.2 volt per light,:D though I did use 12mm power cable because that was what I had.:o
Deano:)
NOTE TO MODS.
I DIDN'T KNOW WHERE TO POST EXACTLY, FEEL FREE TO MOVE IF NECCESSARY.
This post is about fixing the head, side, tail and instrument lights in this model Defender. I don't reckon there'll be much difference in similiar Defender models but I can't say for sure.
What is really handy is a copy of the vehicles circuit diagram, though basic fault finding can be done without it. ( A lot easier with it though).
Pages 43.3 & 43.4 refer. (though is only 32 pages in total).
For this sort of testing/fault finding it's best to use a test lamp NOT a multimeter. :)
A copy of a the '97 model year' Defender circuit diagrams can be found here.
http://www.legionlandrover.com/manuales/electrical%20schemes%20-%20defender%20300%20tdi.pdf
This manual, though for a 1997 model is the same, so far, for my 1995 model.
Lighting circuit description.
Lighting power is fed from the battery via a fuse panel mounted in the engine compartment next to the 'heater box'.
https://www.aulro.com/afvb/images/imported/2012/05/873.jpg
Link 1 powers the lighting. It's the one on the left (30A) and is at the rear of the fuse box closest to the firewall. Link 2 feeds the ignition switch, also important for lighting (as ignition must be on for the headlights to work), Link 3 (60A) does the glow plugs and Link 4 feeds the aircon (20A in photo but should be 30A).
Note. These large fuses are referred to as links (as in fusable links) and shouldn't be confused with the fuses in the vehicles cabin which will be referred to as FUSES.:)
Link 1 feeds the main light switch (LHS of steering column) which is a three position switch. Pos 0 (closest to driver) is off, pos 1 is park or side lights, tail and instrument lights and pos 2 is headlights.
Note. Ignition must be on for headlights to work.
The main fuse panel is in the cabin and looks like this.
https://www.aulro.com/afvb/images/imported/2012/05/874.jpg
There are 20 fuses in the fuse box. They number 1-10 (left to right) in the upper row and 11-20 in the lower row.
Note. In the above picture Fuses 1, 10 & 20 are not installed.
From the main light switch [SWITCH-LIGHTING (S100) on the circuit diagram] the 1st switch position (park) feeds power (from brown wire) via the red wire to fuses 15 & 16. Fuse 15 (5A) feeds the front LH side light and the rear LH tail lamp. Both these lamps should be 5 watt. Fuse 16 (5A) feeds the front RH side lamp and the rear RH tail lamp (both 5 watt). Fuse 16 ALSO feeds the instrument panel side lamp warning light.
If you don't get this far you've probably got a blown fuse or a crook light switch, probably the light switch, but more on this later.
Things get a bit trickier when the headlights are switched on. The above circuit remains activated when the headlights are switched on.
Power is fed from the main light switch (now on pos 2) via the blue wire to the RELAY-HEADLAMP (R123). This relay is mounted underneath the fuse panel and is the relay on the LEFT (yellow in picture but can be any colour).
This relays function is to ensure the headlights can only be on when the ignition is turned on. It is not a headlamp relay in the conventional sense in that it DOES NOT relieve the main light switch of the headlamp current load.
If you suspect that this relay may be faulty, or that it provides a 'feature' you don't desire or that you don't want to have the ignition turned on whilst fault finding it can easily be disabled/bypassed this way.
https://www.aulro.com/afvb/images/imported/2012/05/875.jpg
This relay operates whenever the ignition is on and directs the headlamp power to the columm mounted dip switch [SWITCH-COLUMN (S123)], (blue wire in blue/red out) to fuses 11 &12 via RELAY-DIM DIP (R126) on the circuit diagram.
On my basic defender the RELAY-DIM DIP (R126) does not exist. It appears to be a light dimming timer relay that may be provided on more 'upmarket' or later models. Never the less its plug in base is hidden up behind the dash. On my Defender a 'dummy' relay was provided. This dummy relay provides a 'short circuit' connection between contacts C048-8 and C048-2 (on the circuit) which are the two blue/red wires.
https://www.aulro.com/afvb/images/imported/2012/05/876.jpg
This relay (red box in picture) is hidden up behind the instrument panel and (in my case) is nothing more than an expensive short circuit connection between the two blue/red wires. In my case this was faulty. The connectors between the red 'can' and base had heated and melted the plastic resulting in a poor connection. I cut the blue/red wires from the base and soldered them together in a 'proper' short circuit to fix the problem.
Again, to simplify fault finding or to remove an unwanted feature this relay/short circuit module can be removed and a link placed between the two blue/red wires to simplify things.
From here the blue/red wires feed via Fuses 11 & 12 to headlamp RH and headlamp LH respectively.
When high beam is selected the output from the columm mounted dip switch SWITCH-COLUMN (S123) is directed through the blue/white wire to the high beam warning lamp and via Fuse 13 & 14 to the LH & RH high beam headlamps respectively.
Headlight Switch
As there are no headlight relays the full lighting current load is fed through this headlight switch. Total load is around 12 Amps, and this is for the standard 55W/60W headlights. Don't even think about higher wattage globes, the system was marginal when new for the original globes.
The headlight switch is the weak link in the lighting chain, essentially it is a 'made to a price' component that will fail.
https://www.aulro.com/afvb/images/imported/2012/05/877.jpg
https://www.aulro.com/afvb/images/imported/2012/05/878.jpg
The switch contacts are fitted in a piece of white plastic. If (when) the contacts heat up with the lighting current flow the plastic softens and the copper contacts 'sink' into the plastic and become a poor connection due to less contact tension and/or melted plastic on the contact surface(s). As the copper contact 'regresses' into the plastic its riveted connection on the bottom side of the plastic plate also loses tension compounding the poor connection problem.
A new switch costs somewhere between $20 (UK) and $80 (Aus) and will ultimately fail again anyway unless something else is done.
What I've done (above) is push the contacts back through the plastic and solder the contact connection/rivet on the underside. The heat from the soldering iron softened the plastic and made this easier to do and has hopefully now 'set' the contacts back in their original position. A close look at the first switch picture shows a gap between the plastic and the copper contact, this gap could be filled with some sort of glue/epoxy if you were keen enough. The rivet/contact plate connection is clear on the blue wire (headlight) connection on the second light switch photo.
The overall goal is to decrease switch contact 'stress' by installing headlight relays which decrease the switching current. This also increases the lighting efficiency as there is lesss voltage drop getting the power to the headlights.
https://www.aulro.com/afvb/images/imported/2012/05/879.jpg
This picture shows a high beam and a low beam relay on the passenger side, duplicated on the drivers side. (There is an extra red power cable in case I install driving lights later).
Switching current on the lighting circuit has been reduced from around 12 Amps to less than 2 Amps.
Total cost was less than the cost of a new light switch, though I did have the cable lying around.
I ran the power cable to the relays from the back of the alternator and used the existing earth return. Total voltage drop is 0.2 volt per light,:D though I did use 12mm power cable because that was what I had.:o
Deano:)
NOTE TO MODS.
I DIDN'T KNOW WHERE TO POST EXACTLY, FEEL FREE TO MOVE IF NECCESSARY.