1991 110 300Tdi Battery Disconnect....

Evening....

Our 110 has a Disco 300Tdi engine fitted....

In the under seat battery area is the famous 'Spider' unit.....it is not bolted to anything so I assume it was transplanted along with the engine from the Disco....

Behind the instrument binnacle is the Green Box which I assume is the alarm.... this looks to be factory fitted as it is quite buried in there and bolted to the bulkhead!!

When we bought the vehicle we got keys but no alarm blip thingy (don't even know is there was one in the first place!), never needed it as the alarm has never gone off...so supposedly it hasn't been set....

On the binnacle is the red LED tell-tale lamp....with ignition off this blinks, when you switch the ignition on and while the engine is running, this remains on steadily.....

I need to disconnect the battery, but I am conscious that I may either set the alarm off (if it indeed works) or immobilse the car from the Spider.....

Now I do have the Spider Bypass Plug as I was having intermittent starting and cutting out issues....just never fitted it as I found out this was due to a dodgy ignition switch....I very carefully fitted a new switch without disconnecting the battery, but tonight I want to disconnect the battery so I can do both a bit of a weld on one of the suspension spring retaining brackets and also I want to make a battery restraint strap, and need to get the battery out so I work in the seat box....

What do you more Defender knowledgeable chaps think may happen and possible remedies should they do so???

Hmm personally I'd remove the battery and take the chance. The spider system can easily be removed. I came across the removal Instructions yesterday by accident online so I know they are there.

IamRobbie said:

Hmm personally I'd remove the battery and take the chance. The spider system can easily be removed. I came across the removal Instructions yesterday by accident online so I know they are there.

Click to expand...

Cheers, chickened out on Friday so did it tonight instead!!

Had a look around for a BBUS sounder or horn, but found none, although there was a lone brown multiplug in the L/H wing area behind the head lamp so I assume that's where it was!!!

So took the plunge and disconnected the battery. No alarm went off so that's good!

Disconnected the spider unit and plugged the bypass in....I know it can be done without having to buy the bypass plug, but I bought it ages ago before I had found the wiring info online!

So to give it a test I reconnected the battery and went to start the car....started fine, but the indicators flash constantly as if the alarm was going off...!!!!! After much head scratching and thinking about taking the Alarm unit out and cutting the wires to the flasher unit, but I found a hidden switch that appeared wired to the alarm unit....played with this and the lamps stopped flashing!! Handy!

So I am now 'reasonably' confident I can disconnect the battery without to much going wrong.

My 300 tdi once decides to stop locking and unlocking with the fob. Instead it thought it was a boat with the stupid fog horn alarm and the flashing light bollocks it does. I found a way to re program the fob with a series of ignition switching and door locking... What a Ballache, however before getting to that stage I found unplugging the alarm horn works a treat. I'm glad it worked for you.