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May & Scofield Alarm location

9K views 64 replies 8 participants last post by  Camaro16 
#1 ·
Does anyone know where the main unit for the M&S unit in a UK ZG Grand Cherokee?

At my wits end and facing scrapping this great car... I am left with little alternative other than to give removing the whole system a go as sourcing this DEI 455T bypass seems to be a pipe dream. I've managed removing alarms on a couple of other cars with aftermarket alarms - including a particularly messy one in a German sports car.

I've read a few people say it's tapped into the PCM, and I can see the wire - but I can't believe that the alarm came with a specifically revised PCM module. Noticed a couple of posts where people claim to have removed it without a problem yet sadly these are never substantiated or offer any detail. My experience is that the piggy back existing wiring, therefore they can be removed!

Having removed the panels under the steering wheel I cannot see anything obvious. Can anyone offer any pointers / photos?

Any help would be much appreciated!

I may be new to JeepForum but I am a long time forum user and as someone who relies on them to solve issues I value those who give back the info to the community.
 
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#2 ·
Some areas to check, because I dont have a clue,would be behind the glove box, or perhaps behind the instrument cluster.
 
#4 ·
@Camaro16 seems pretty sure and to be honest that's the best thing I've had to go on so I'll take his word on it.

Incidentally I've heard back from the guy at M&S so will see where the advice takes me. What would you want for a 455T? I am in Austin at the end of the month so shipping could be easier. There's some good junk yards there too... :laugh2:
 
#5 ·
I've seen them all over the place - behind the headlight switches, glovebox, anywhere they could get to. Once you have bypassed the M&S immobiliser you'll still be stuck with the US installed alarm, which is why you want a 455t. and yep, A 455T will work on a ZG - I have it on 3 of them!
 
#16 ·
Hi, another ZG owner here, with the dreaded immobilizer shutoff problem, after changing a water pump and stat in january 2017, everything at the time wet and frosty,bad for the electrics... my alarm started to go off on its own, tried all the tricks, battery disconnect, check earths etc,but the ecu is stuck in shutdown mode.
The ZG has been an ornament in the driveway for two months..

Have sourced a 455T, which is arriving from Texas new and unused and premium price paid, some time this week.
Still cheaper than towing to the dealer stealer.
Just need some clarification when I have bypassed the M&S alarm,joining black wires 21 and 22, how to connect the 455T to what unit behind the drivers side to fool the ECU,any help will be much appreciated..thanks in advance:grin2:
 
#6 ·
Oh, when you find the m&s alarm, it is wires 21 and 22 you want to cut and connect together, as they come from the black connector. Then it should stsrt for a few seconds, then stop dead. That's what the 455t will sort out, it's the US security system built into the PCM.
 
#7 ·
I've had a reply from Del at M&S, who has been exceptionally helpful, and he seems to think I should start by replacing the RKE / window switch unit. What I am not sure about is whether it is possible to swap out the RKE and Fobs with a unit from another car... I think you can do it on a WJ but can't find anything about anyone doing it on a ZJ/G
 
#9 ·
Yep, that was me - the bloke who was meant to be the forum guru flat-out denied that I could bypass it with a 455T!
And you can indeed get the RKE from another car - you don't need the fobs, the RKE doesn't do any decoding.
I know this because I recently mashed my driver's door, swapped it for a same-colour door from my spares ZJ, and the original fobs worked perfectly.
Del is the same guy I spoke to, many years back - nice guy, very helpful.
 
#11 ·
This forum is no different just like many other forums. It has more then it's share of keyboard mechanics. These keyboard mechanics simply pass along what they read as their own. Very little real world experience and a ton of hypothetical theories passed of as experience. They couldn't tell the difference between a left-handed and right-handed monkey wrench.
 
#12 · (Edited)
So spent a bit more time on the weekend and found the alarm control unit in my car, behind the light switches on the right side below the dash dials of my RHD steering wheel. Unplugged the closest plug I could get my hands on (there are 5 plugs going into/out of the thing) and the car will run for a few seconds and then cut out, as described by other posts of US models.

Tonight I will ground the purple / yellow wire to see if that at least means I have a mobile car, albeit with no dash dials whatsoever.

Del at M&S suggested I try an RKE unit from another car. No idea if it would be plug and play and in the absence of any 455T modules around this sounds like one of my only options. Cant find any RKE's for sale, but probably will prove easier to find than a 455T (unless of course @Camaro16 has found one he could spare? :wink2:)

I also tried many of the various user fob programming methods outlined on a host of sites, but no luck there.
 
#13 ·
Grounding the yellow/purple light on a 96-on ZG will leave the interior light on permanently, and won't bypass the immobiliser/alarm. And I'm afraid I only have 2 left - that's basically 2 free jeeps when I find a dead one in the scrappie with immobiliser problems, so I'm afraid I won't be selling!
 
#17 ·
Hi, have been following the threads on GC cherokee immobilizer fixes. I have a GC 1998 ZG, which had problems in January 2017, ECU is now stuck in shutdown mode and has been immobile for couple of months. 455T arriving from Texas this week, brand new unused old stock at a premium via the global shipping ..ouch! but still cheaper than towing to dealer.
I'm fairly proficient on mechanical stuff , having owned this GC for over 10 years, and kept it well maintained, can figure out earth and 12 volt supply for the 455T, but stumped with remaining connections to fool the ECU. Would be extremely grateful if you could send by reply any information on installation of the same, with pinout info for the M&S plug and where to connect to the PCM and locations of the connectors, regards and thanks in advance.
 
#18 ·
There is a large black and large white connector coming from the M&S module - cut and join wires 21 and 22.
Wiring diagram is here - http://www.directeddealers.com/manuals/ig/accessories/N455T_04-98.pdf
All you need is the top two wires ((white/black and violet/brown)they go straight to the OBD2 port wires of the same colour)), the black and the red wires (+ve and -ve), and the blue wire (touch it to an earth via a momentary switch to disarm the alarm/immob).
It'll act just as if you had disarmed it using the fob. Simple as anything.
Unless you want remote start or any fancy options, ignore the rest of the wires!
 
#22 · (Edited)
Hi, I'm awaiting delivery this week for the 455T,it's currently stuck in Hatfield at the courier depot awaiting dispatch, took 8 days so far from the lone star state to get to the UK.
the Seller is on E Bay, mando987270 search via ebay sellers usa, he's in Laredo...yeah the streets of..careful they all carry guns there...lol
Originally the listing was USA only, but I pleaded with him, and eventually he relisted as a buy it now for international shipping...not much change out of 142.00 quid includes 20% vat and 1.5& import taxes via global shipping...so quite expensive! regards
 
#24 · (Edited)
not much change out of 142.00 quid includes 20% vat and 1.5& import taxes via global shipping...so quite expensive! regards
Ouch! Hate to tell you I found and ordered one for $50 with free shipping which I hope gets to me before I leave! If I see any more at that price I will bring them back for other forum members who I am sure will crop up!
 
#25 · (Edited)
Ha Ha good for you!
BTW this wasn't my first rodeo...a cautionary tale
In 2004 I owned a Mk 1 XJ 1994 4.0L cherokee classic green which i had had converted to run on lpg, originally bought in 2001.
On a trip back from the west country around xmas time, the transmission developed a leak, topped up at a service station and limped home. Took to the local main dealer for a diagnosis the following day, at the time just a couple miles away.
They told me after a few hours i needed a new transmission, and they could fit a recon for 3500 quid!, they had also washed the car and charged me a hundred quid for telling me what i already knew,the most expensive car wash ever.Anyway searched around on the net for a local auto repair specialist, and found a garage in Haverhill about 40 miles away, told them my sorry tale, they gave me a quote for 900.00, and chucked in a courtesy car, and collected the jeep, fully reconditioned the box, replaced some brake bands and rebuilt aok, with one year warranty, all done within four days for just over a grand.How these main dealers get away with robbery escapes me.
I ran it for another year AOK no problems, and sold it on to a satisfied buyer, and then bought the GC, also converted to run on lpg at the time.With the price of fuel rocketing over the past decade, this 4X4 doesn't owe me anything, running at 50-60 pence a litre over that period.Prior to retiring from the day job, I toured around most of East anglia gigging in a band evenings and weekends, lugging kit, in a very reliable vehicle which was cheap to run.If this fix works I will probably run it for a few more years....Good Luck!
 
#28 · (Edited)
Hi... haven't done anything yet, the GC isn't the centre of my universe, it's an as and when, now i've got all the bits, prior to all this I had to give my daughter's old zetec a major service when a water pump failed and also blew a core plug around xmas time, so spent several weeks fixing that, which involved dismantling the driver side of that engine to get to everything,an absolute pig to work on... anyway another story, all fixed up now and running well, so i helped her get another vehicle in february, and i'm zipping about in her old car. ho hum...let you know whenever ..regards

p.s. I've ordered another box of roundtuitts ....you know the rest.
 
#29 · (Edited)
Well I made a start this weekend, dismantled the dash, kicker panel, and removed the light switch/speedo dial unit to find the m&s alarm unit...pictures below...the odb unit is easy to remove, just two screws, have connected the cut bypass wires 21 22 away from the plug, conveniently you can see the numbers on the plug but you have to lift the unit and turn through 90 degrees to the left to get at the plug wedges for the right black plug, careful with the little plugs and connectors on the left as they are connected to an exposed part of the pcb, with age they get quite brittle, they have to be disconnected as well..Anyway have done the bus connections and bypass, just have power and earths to do and we'll be good to go,however waiting for a dpdt switch to arrive, for my radio antenna, i'd installed a manual switch for it when i first got the GC, and that needs replacing, got a bit tired over the years.
 

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#30 ·
Looks familiar! So not quite a 30 min install as I've read somewhere else. Which does not come as a surprise. Thanks for posting the pics though, very useful.
I spent some time working on my car on the weekend and installed a nifty multipoint power adaptor in the boot/trunk - has some USB power points, battery voltage reading and a cigarette lighter socket so that I can run my refrigerated cooler box when it's in the boot. Also picked up some clear indicator lenses for the front which required me to cut and solder on new connections as the US indicator lenses used a different bulb socket.
Going to install my 455T this weekend as it's a long weekend in the UK. Will post some pics if I encounter anything worth noting.
 
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