Broken Ground Strap-Where does it Go?

[neophyteguy]

Well, todays joy was to methodically work through the grounding straps (that I could find) and then to remove, wire brush the connecting point and all hardware and then to replace.

On the rear side of the cross member where the starter ground is connected, there was a grounding cable. It was connected to the cross member and is about six inches long. The ring was half broken off and I couldnt find where the other end connects. ANY IDEAS?

Also, does anyone have a definitive list of where the straps are on a SIIA, late model-71?

Cheers,
Ronnie

[Slunnie]

Not just to the engine block is it?

[neophyteguy]

nah, isnt that long........Looks like it would only reach the gearbox, but even then I wouldnt know exactly where to connect it.

[JDNSW]

The only earth straps listed in the parts book are from the battery negative to the radiator support and from the starter to the chassis plus wiper motor to windscreen. But bad connections between panels and from panels to the chassis mean that most Series Landrovers have had extra earth straps added - many for example have the battery negative to the engine block (mine has).

It is essential to have earth straps from somewhere on the engine/gearbox assembly (does not matter much where) to the chassis and from the radiator support to the chassis or battery negative. Provided all these are in good shape it does not really matter which one the battery is earthed to. In addition to these, a strap between the bulkhead and the engine or chassis may be necessary.

The largest current drain is the starter, so the connection between the engine/gearbox/starter to the battery, whether direct or via the chassis. The second largest drain is the headlights, and the original setup relies on panel to panel and panel to chassis connections - these are not reliable, so you need an earth strap to the chassis or engine or battery from the headlight earthing point. Originally the bulkhead will be well earthed to the chassis, but after at least 37 years, it is likely that it will not still be, and since a lot of things are earthed to it, a strap to engine or chassis is a good precaution. The rear lights are earthed to the chassis, so no earth strap to the tub is necessary.

John

[neophyteguy]

John,
Thanks for the outstanding feedback! I attached the mystery strap to the gearbox.

Further to your advice, I also ran a cable back to the battery from the ground where the headlights are connected. My battery was already grounded to the right front of the block where there is a wire holder/mount also attached.

I ended up finding a couple of other ground wires which were running from the switch and the instruments which were grounded on the bulkhead! All have been cleaned and I am hoping this will help now that I am on to sorting out the electrics.

While I had the instrument panel unscrewed today, I replaced the interior light switch and then I think my ignition switch grounded while I was moving the plate. I heard a sound which sounded like a fuse going. From then on I have no lights on the dash, interior lights dont work and exterior lights dont work. Actually the map lights do work, but not the instrument lights......................

Is it possible that I shorted out the switch? I already have a new one ordered from earlier in the week, so not an issue if it is, but I dont feel confident this is what it is.

I also looked for any inline fuses in the wiring and didnt find any. ANY thoughts anyone?

Oh what have I created for myself now?!?!?!?!?!

Ronnie

[JDNSW]

John,
........
While I had the instrument panel unscrewed today, I replaced the interior light switch and then I think my ignition switch grounded while I was moving the plate. I heard a sound which sounded like a fuse going. From then on I have no lights on the dash, interior lights dont work and exterior lights dont work. Actually the map lights do work, but not the instrument lights......................

Is it possible that I shorted out the switch? I already have a new one ordered from earlier in the week, so not an issue if it is, but I dont feel confident this is what it is.

I also looked for any inline fuses in the wiring and didnt find any. ANY thoughts anyone?

Oh what have I created for myself now?!?!?!?!?!

Ronnie

The only fuses in the standard circuit are for the accessories switched by the ignition (blinkers, gauges etc) and a second fuse, unused in standard configuration. Both are in the fuse box on the engine side of the bulkhead. My guess is that the momentary short has used a wire or a connection as a fuse. Looking at the wiring diagram and my memory of the arrangement it is a bit hard to see just where to look, but I would look at the connection between the light switch and the ignition switch - check for voltage there using a test light or a meter. This does not feed through the ignition switch but is attached to the power feed to the ignition switch from the voltage regulator (if the generator has been replaced by an alternator the voltage regulator may be in place and acting as a terminal block, or may have been removed and the wires joined there). It is quite likely that there have been significant wiring changes made through the years, and this may affect the above information's accuracy!

As the lights are not fed through the ignition switch, damage to the switch will not stop the lights. If the wire supplying power to the ignition and lights is damaged, it can be replaced by a separate wire taped to the outside of the harness, but beware of other wires that may have been damaged inside the harness.

It is good practice to disconnect the battery when removing the instrument panel (and many other operations as well), and only temporarily connect it for tests while the panel is out - now you know why!

John

[neophyteguy]

John,
Thanks again! Unfortunately, after having spent several hours on this today, I still couldnt resolve the issue. I dont have anything working in the car other than the map light.

Yes, I do have an alternator and the voltage regulator is still in place. Im not sure if it is being used as a terminal block or not.

I did notice the positive lead off the battery goes to a junction of some sort. This junction looks like it has some sort of electrial bit below it. The only power I have coming off this junction box are actually from the terminal where the battery positive cable connects. The other two do not have power. One of these other terminals is the positive for the starter and the other runs to the switch.

I couldnt get any voltage between the light switch an ignition switch. There is a cable splitting off from the aforementioned terminal. This is tied into a cable which runs to the alternator and also runs into the cab. It does deliver 6v to the ignition switch. Not sure where the rest of the voltage is dropping.............

Any ideas anyone? I really dont know where to go from here. Any electrical Gurus in Melbourne?

Cheers,
Ronnie

[JDNSW]

John,
Thanks again! Unfortunately, after having spent several hours on this today, I still couldnt resolve the issue. I dont have anything working in the car other than the map light.

Yes, I do have an alternator and the voltage regulator is still in place. Im not sure if it is being used as a terminal block or not.

I did notice the positive lead off the battery goes to a junction of some sort. This junction looks like it has some sort of electrial bit below it. The only power I have coming off this junction box are actually from the terminal where the battery positive cable connects. The other two do not have power. One of these other terminals is the positive for the starter and the other runs to the switch.

I couldnt get any voltage between the light switch an ignition switch. There is a cable splitting off from the aforementioned terminal. This is tied into a cable which runs to the alternator and also runs into the cab. It does deliver 6v to the ignition switch. Not sure where the rest of the voltage is dropping.............

Any ideas anyone? I really dont know where to go from here. Any electrical Gurus in Melbourne?

Cheers,
Ronnie

The "junction box " is, from your description, the starter relay! The cable running into the cab will be the one that supplies power to everything. It would seem to have developed high resistance as a result of your short. This will be either because the wire is burnt, or if you are lucky, the contact at the starter relay.

Try disconnecting the battery and then undoing the connection on the relay and clean everything up using a small wire brush, and see if that gets anywhere.

The interior light is probably the only thing working because it is the only thing that takes a small enough current that the voltage drop leaves enough for it to work.

John

[neophyteguy]

Ok, I took all connections off the starter relay and cleaned and replaced. There were no burnt looking connections. On the post where the batter lead (+) is connected, there are 2 other connections. One (#1) wire goes to the bottom section of the fuse box and has 12v running through it. The other (#2) one ( heavier wire) splits off in two directions. One piece is connected to the alternator and the other is connected to the ignition switch.

At the ignition switch there is occasionally 12v. If I start at the relay and track the voltage--12v at the relay, 12v at the junction which heads off in two directions and 12v at the end of the wire. If i plug this wire into the igntion switch and turn the switch on and then off, the voltage drops to about 4v. It stays this way no matter how many times I turn the ignition on/off or reattach the test leads. Sometimes the 12v which reappear and other times I have to go through the tracking of voltage from the relay again in order to get 12v at the end of this line............

The only other place I have voltage in the cabin (other than map light which always works) is at the blackout switch. I started replacing all connections at the blackout switch today, but ran out of connections. I will finalise this tomorrow. Off the terminal on the switch where the voltage is, there is a wire which runs directly to the interior light switch and then on to the interior lights. NOT really sure how this would cause the headlamps to work/not work but will hopefully get the switch sorted tomorrow.

So, I took a punt just now and connected the #1 wire to the top section of the fuse box. I was able to use the wipers and the green light on the dash came one. This was independent of the switch being on or off. The dash lights and the headlamps would not come on.

Any help is greatly appreciated, Ronnie

[JDNSW]

If you have 12v on the end of the wire while it is not connected to anything, but this drops to 4v, you either have a bad connection somewhere back towards the battery (could be between the wire and the tag on the end of it) or there is a short in the ignition switch or beyond it. To tell which, use this wire to try and run a bulb such as a headlight bulb, that takes a fair current. If it runs that without a voltage drop, you have a short somewhere on the ignition switch or beyond. If the voltage is dropping between one end of the wire and the other - replace the wire.

The reason connecting power to the top of the fusebox has that effect is that you have in fact bypassed the ignition switch, and supplied power to those services that only have power when the ignition is on.

John

[UncleHo]

G'day Neophyteguy :)

This 1971 2a is an ex-army one ??? as you mention a Map light, has it still got it's Blackout switch?, there is an earth wire (battery cable size) between the left engine mount lower bolt and the upper bolt (bridging the rubber mount) that is chassis to engine block, the other one is from gearbox X member to bellhousing,there might even be light woven straps between bonnet and firewall,this vehicle being a Negitive Earth production would have keystart ignition, there would be the following on the starter solenoid switch, battery in from + soloenoid to starter,2 brown wires from +solenoid term to-reg term"A" not A1,and brown to Horn,spade terminal wire(red/white to Ign switch)this is the energiser wire, the fuse box (2 fuses) has upper permanent power,lower ign powered,(wipers,blinkers,coil,stop)horn could be through this,that is about all I can help at this time will go and look at my 68 military 2a wiring(-E) later for you :)

cheers

[neophyteguy]

John and Uncle Ho,
Firstly, a huge thanks to you both for your time in helping me work through this! Yes, this is a military 2a and has a blackout switch.

After printing out both of your previous responses (and having taken a couple of days away from electrical systems!), I started to work through this again.

When I looked at the back of the black out switch, the terminals didnt look very usable. In fact, a couple of the terminals looked black, but they didnt look like they had been freshly fried. Either way, they were replaced.

I then went back to the battery and tracked voltage through the system again. Even though I had done this literally dozens of times, I thought it a good idea to check all terminals and connections again. So, voltage to the starter relay was fine.

It was getting late and the warehouse lights were warming up when I checked the voltage from the relay to the lead which goes to the switch. Low and behold, I got a little spark! At the time I was using a test lead and had been checking voltage by placing the voltage on the tab coming off the relay rather than necessarily placing the test lead on the connector.

So, what was happening was the connector was actually shorting through the test lead on to the tab on the relay. I had the light switch on and was alerted to things happening when the headlamp shined on the roller door. Woohoo!!!!!!!!

Turns out the connector at the relay wasn't really making a great connection. It was a good enough connection to carry voltage, but when more was asked of the connection, it was failing. Ive never seen anything like this before.

The connection was a large push on type connector which was soldered on. It was the type of connection that it would be hard to ever doubt!

I will be replacing this cable all the way back to the switch later this week.

I am not sure if the voltage was being lost over both the blackout switch and the connector or just the connector.

Thanks again for your help guys! I very much appreciate it.

Ronnie