Regrounding TD5

[carlosbeldia]

Some time ago I read about how to reground a Defender TD5 in order to eliminate some little problems with electric and electronic systems. Now I have some time to make this regrounding mission, but I can't find this mentioned topic. Can somebody help me with this? specially, I'm interested in fix a little problem with my Nanocom: when used as instrument, it generates a very frequent error, it's really annoying..... thanks in advance for any reply.

[black-ibex]

From the Nanocom website:

"For the DEFENDER vehicle often you just need to clean the ground ring terminal of the ECU's wirings located in the seatbox near the engine ECU. For the discovery the problem is harder because the ecu wirings are more complex and sometimes it is different because the cars has different equipements installed. Anyway the main ground connection of the Discovey is located near the engine ECU and the battery. Sometimes can also happen that the ground problem is in the OBD soket itself, so is possible to connect the pins 4-5 directly to the battery."

[carlosbeldia]

Thanks a lot, Black. Both pins must be connected to battery lead? negative or positive lead (I suppose it's negative, but prefer to be sure...)? I think those are the new ground points they mentioned in the article. What kind of wire do I need?

[Se7enUp]

I ran a new earth wire from the battery, to the ODBC connector, then onto the ECU.

If you look underneath, there is already a section of loom that runs from the battery box to the ECU seat box. I followed this route.

Adding the additional earth cured my Nanocom's connection problems and stopped my temperature gauge from moving about.

[carlosbeldia]

Seven, the earth you are talking about goes from battery to what pin of the OBDC conector? and from there to pin 4 or pin 5 (or to both?)? what kind of wire did you use?

[carlosbeldia]

Seven, also (and please forgive my ignorance) can you tell me if wire comes from positive or negative lead?

[Se7enUp]

-ve

I don't have the vehicle now - or the Nanocom (both now sold), however the Nanocom website has a diagram showing which pins to earth.

here you go

I basically joined the ECU earth post (under the seat just below the ECU) to the recommended pins (4 and 5) on the OBD connector to the -ve terminal of the battery.

I used standard automotive cable - sorry, not sure what gauge or rating it was.

From memory, it was a very similar size to the cables going to the OBD connector.

[carlosbeldia]

Seven, sorry in being such an idiot, but there's a final question: pins 4 and 5 have a wire each or I must use one for both? also, this OBD connector is the one that I use for Nanocom issues, right? so this is the way:

Wire(s) going from -ve to pins 4 and 5 of OBD connector

wire(s) going frome pins 4 and 5 to ECU ground?????

Thanks a lot for all your patience....

[Se7enUp]

I ran a wire from the -ve of the battery.

This went to the OBD plug (that's used to connect the Nanocom to) where it joined the existing wiring (that goes to pin 4 and 5).

The new wire then carried on, into the seat box and connected to the earth post under the ECU.

This mod has the following effect.

It ensures that the ECU earth (post) is at exactly the same potential (voltage - in this case 0 volts, -ve or ground) as both pins 4 and 5 of the OBD connector.

Battery(-ve) -> Pin 4 OBD -> Pin 5 OBD -> ECU earth post

Basically, join the wires for pin 4, pin 5 of the OBD connector and the ECU earth post to the battery -ve using a single wire

[carlosbeldia]

Thanks a lot Seven, it's now clear to me, I'll do it and let you know....

[carlosbeldia]

OK, it's now done, zero Nanocom problems since then, thanks Steven... besides earth from battery to chassis, ECU and ABS control units to earth posts, and from right underseat to chassis, is there any other earths?

[SiWhite]

I found one today that was causing a few problems - directly in front of the instruments in the engine bay (i.e above the steering column) there are two earths - one is a single ring terminal, the other is a junction of a few earths, which come together in a white box that has a single ring to mount it somewhere. Not having these earthed means none of the instruments or lights, wipers etc, will work.

[carlosbeldia]

Thanks a lot, i'll find it tomorrow.

[carlosbeldia]

Hi there. I have tried to find the white box or grounds but with no results. Now I'm having an annoying problem: sometimes I push the brake pedal and ECU, brakes and oil lights gets on (as engine was shut off) while I have the brake down. As soon as I release the brake everything comes back to normal. Today I press the pedal and all instruments went down (fuel, temp and speedo), however Nanocom still showed values in instrumental mode. Normal grounds appears to be ok, what else could it be? My car is a 2001 (MY99), is there any chance the white box didn't come?