mckrob85

Right, as some of you know, i had an alarm issue where by the alarm siren would trigger randomly, and annoy my neighbours.

In the UK we have an insurance system where if an alarm system meets 'Thatcham' class, 1, 2 or 3, you get a better rating and insurance gets cheaper. This is why the USA doesnt seem to have a siren, you have horns to sound the alarm, in the UK dealers fitted Thatcham sirens when new. So anyway, the siren was tucked away behind the ECU, barely visable even with the ECU removed completely!

So i cut the wires running to it and pulled it out, no more siren! Great....

Well no. As now the car wont start. No start and stall, just key turn - silence. All guages and lights work fine. I left it overnight and turned the key the next day and it fired right up, went for a drive, came back, turned off and on a few times and thought problem was solved. Now its dead again, no crank, no start. I thought perhaps its the immobiliser, but wouldnt it start then stall if this was the case?

I've read about shorting the starter solenoid to the battery to start it, does this bypass the immobiliser? Are there any tricks to start it, or perhaps a way to completely remove the security system? I need a way, even if its a little switch running from starter to battery, to have the jeep start as currently its dead in the water

I rang Jeep UK and all he could suggest was jiggling the gear stick while trying to start it, and trying to start it in neutral, other than that they need to hook it up to a meter, which as the jeep isnt moving, isnt an option, and with me having removed the siren box, might be a wasted trip if it throws up no codes.

The battery is a new one, everything functions as normal. Any help desperately appreciated.

1996 ZG Grand Cherokee LTD

dave1123

Frustrating, ain't it! I would like to know how to eliminate the security system also! I'm sorry I can't help you with your problem, but I'll watch your post and offer any help I can. When all is said and done, a simple switch in the ignition circuit works well, has for years before alarm systems were thought of! There are even heavy-duty locking switches that mount right on the battery post used for heavy equipment!

I don't know how you feel, but I don't want a piece of electronic crap telling me I'm not authorized to operate my vehicle!!

mckrob85

I would like too add at this point that using the keyfob unlocks doors and turns red LED off.

Any suggestions?

leadpipe58

Contact the company that makes the alarm system and ask them how to remove it.
There may be a forum for that like this Jeep forum.
Good luck

mckrob85

Its a bog standard OEM Jeep alarm! Just the UK spec differs from the US in that we have a seperate siren.

Took the lid off the PDC and relay 'E' is clicking when turning the key to the start position. Its the starter relay, is this normal? I took it out and switched it with relay 'L' which is the horn relay, and tried again, with exactly the same outcome, just clicking.

Under starting conditions, battery reads 11.85v.

Is there a trick to starting it by shorting something out on the starter motor itself, whilst turning the key? Perhaps battery feed direct to the starter?

Im thinking perhaps its not the immobilizer, as pressing the unlock button on the fob turns off the red LED, which must mean its disabling it.

So, is the clicking normal?

Regards

mckrob85

Ok! Right, well, problem is in hand, almost solved.

Turns out that the 11.85v isn't enough to engage the starter, and with a jump from my trusty Transit van it fired right up, so now it seems i've defeated the alarm system, and have a running Jeep

Well, tomorrow i will drop test the battery (new at car purchase) and if thats ok then the alternator will need some attention, or perhaps even screwing around with the Jeep cutting and splicing wires during attempts to bypass the alarm, caused the battery to drain.

Ran out of light tonight so will carry this saga on tomorrow, but so far its a thumbs up

VTSS gone, remote locking still works, Jeep alive!