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Discussion Starter · #1 · (Edited)
Our JeeP Grand Cherokee has just died in the electrical department. Press the remote and nothing. Batteries in remote well over 3v each. All electrical seem to be working but not the central locking and the immobiliser. From what I have researched I suspect the box called a body control module is somehow involved. In my mind I am thinking check the fuse but cannot identify one in the system. For some years now we have had to occasionally disconnect th battery for 10 secs when one of the door modules went to sleep and the drivers door window and mirror wouldn't work. That bit hasn't stopped working so it's anew fault. Anyone got any ideas? I would love to scrap all the modiules and gizmos and hard wire everything like my Prefect as the car is getting on for 20 yrs old and who is going to steal it?
Just found another clue that may be useful. Further to the drivers door sleep syndrome as mentioned above, this time the driver's door is still working but the passenger door has gone and nothing will revive it so far. I have been reading the unhelpful manual and somewhere there is a module that has the receiver for the remote key fob and I think it is one of the door modules. Also, been looking on the web for others problems and it emerges that wires breaking where they enter the door after years of bending back and forth.
 

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Had exactly this issue with one. Its the fob that is issue. Take the fob to bits, give the buttons a clean on the inside and the place where they contact it.

Sadly, the ONLY way round it is with a DRBIII diagnostic tool to program a remote.

The immobiliser uses a rolling code system and requires the VIN to be sent from the body control. In short there is no way to bypass any of the system. I spent many hours trying and researching and contacted the manufacturer of the immobiliser too.

However just read your issue properly... Maybe a broken wire somewhere?
 

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Discussion Starter · #3 ·
I will report back when I have checked out the door cable grommet area for any sad wiring. Thanks for the info anyway as may need it eventually.
 

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it might seem needless expense but one of these will confirm the fob good or not:
Sealey IR & RF Key Fob Tester VS921 | eBay
another thing is some fobs the buttons wear out can you identify what sort are on the board and solder on replacement,
MERCEDES SMART CAR MITSUBISHI NISSAN NATS KEY FOB BUTTONS MICRO SWITCHES x 4 | eBay
i have heard tv shop repairmen will do this for you if your not too confident with a soldering iron.......
good luck
neil
Sorry to contradict but for the jeep, both are incorrect. The tester will still register a busted fob as working (ask how I know!) and the chip works on a rolling code. So without a DRBIII tool, is useless. Even your spare fob, if not used for months, will drop off the current pattern and its game over. The bottom line is without a DRBIII, you've had it unless you switch to a standalone ECU or swapping the whole lot over from a donor. Jeeps are an absolute pain in the ass.
 

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Discussion Starter · #6 ·
Sorry to contradict but for the jeep, both are incorrect. The tester will still register a busted fob as working (ask how I know!) and the chip works on a rolling code. So without a DRBIII tool, is useless. Even your spare fob, if not used for months, will drop off the current pattern and its game over. The bottom line is without a DRBIII, you've had it unless you switch to a standalone ECU or swapping the whole lot over from a donor. Jeeps are an absolute pain in the ass.
Agree on the pain comment. Found from the CD manual that the receiver is definitely in the near side passenger door. This after one section said it was behind the dash and I was thinking scrap the car rather than delve into all that. Anyway, will let you know what I find, hopefully just a broken wire or two. If its not that then I will need to try the other things. Anyone got a spare DRB tool in their tool box. I imagine its a tool that Jeep agants use and connects direct to ones bank account.
 

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Put key in ignition and turn on, do not start it. Turn key off then back on 3 times then leave it on. The trouble codes will replace the mileage on the gauges.
Any error codes for the BCM will Begin with B, surprisingly.
 

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Discussion Starter · #8 ·
Put key in ignition and turn on, do not start it. Turn key off then back on 3 times then leave it on. The trouble codes will replace the mileage on the gauges.
Any error codes for the BCM will Begin with B, surprisingly.
Just tried it. Wasn't sure if you meant do the procedure 3 times or 4 so did both but no codes on the gauge. Car is a 1998 model, assembled in Austria in 1997 - maybe too old for that test? Just one more thing observed. Have had the battery disconnected but it was well charged a few days ago, ie down to one amp rate. When I put it back on charge this morning it went straight onto 4 amps but then down to 1 amp in about half an hour. Thats fairly standard. Anyway, I reconnected the battery for the above tests and in a short time it went back up to 4 amps. Have I got a dud battery or some big drain somewhere? Everything else is working. Will next try a relatively new battery on board to check this one out.
 

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Discussion Starter · #10 · (Edited)
Had another look at the passenger door module and connecting wiring. I tried separating the plug where the loom connects to the door by the hinge but couldn't' shift it. I just wanted to isolate that area to see if there is s break in the wiring. So I just put the grommet back and checked if there was power to the door plug at the module end and there was plus a good ground. Tried the window switch and it sprang to life. Tried the remote and it unlocked. Tried the ignition and the car started. Repeated this three times. Then..... it died again and is still dead. Summary.... did I disturb something in the wiring which worked for a short time? The battery voltage still puzzles me. It was well over 15 when on charge but disconnected from the car. As soon as I connected it to the car circuit it dropped like a stone to just over 12v. and still with the charger connected. There must be a heavy load on it and I know the anti theft system takes a bit but surely not that much.
 

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Discussion Starter · #11 ·
Thanks to all who have tried to help with ideas. I think we are getting closer to a solution but can anyone help with this next question. I have a strong sense there is a component causing a volt drop. I am sure it's part of the anti theft system. Going back years, when the battery was reconnected or changed there was a chirp from somewhere under the bonnet but I never knew where but in the region of the power distribution module perhaps. Lately this has changed to a cluck and then yesterday was silent. The alarm sounder doesn't sound. If I could locate the sounder I would try isolating it electrically. I am thinking this aledged volt drop is stopping the door module from Working as its all associated with the anti theft system. Does this make sense?
 

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Sounder is on the bulkhead, drivers side, under all that crap. It's a swine to get to.

I don't envy you mate, intermittent electrical faults are just the worst!
 

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I use a guy in Hawkwell for my Chrysler ,Detroit motors 01702 547330, he used to work for Chrysler and knows them inside out and has a proper Chrysler code reader he is also really sensible on price.
 

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make sure it's a DRBIII - not an emulator. Having a "proper" code reader is like approaching a 19mm bolt with a "proper" 13mm spanner. It's gotta be the "right" proper tool.
 

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Phantom voltage/current drop, made a lot of money from those in the past.
Get yourself an old filament type 12 volt bulb, not an LED, and either use a bulb holder or solder 2 wires on and put alligator clips on the ends, like this.
https://s14-eu5.ixquick.com/cgi-bin...light.gif&sp=cec14fc7c3f337cbd10be6d60d54ec58
Disconnect the negative lead of the battery and put one alligator clip on the battery and the other on the battery lead. All current drawn by the car now goes through that bulb. If you try and start the engine you will need to get a new bulb and try again, so don't.
If the bulb is on you have a parasitic draw somewhere so start taking fuses out one at a time until it stops, now you know what circuit the draw is on.
Start with that and go from there.
 

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Discussion Starter · #16 ·
I did that except I used a Lucas ammeter and this indicated about 3 amps and this should be for just the under bonnet lamp and the anti theft stuff. Another thing Is whatever is cutting off power is also cutting power to the left side rear door as well as the front. I am just wondering if an intermittent relay somewhere is to blame. Back to the wiring diagrams etc but will bear in mind man in Hawkwell and check also which magic wand he has. By the way, thus morning had a half hour to fiddle with the car and just once it came back to life on the left side and engine started. Turned off and it was dead again. Dodgy relay?
 

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my man in hawkwel diagnosed 2 issues with my voyager without even plugging his code reader in both were correct, sometimes experience is better than electronic wizardry.
 

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make sure it's a DRBIII - not an emulator. Having a "proper" code reader is like approaching a 19mm bolt with a "proper" 13mm spanner. It's gotta be the "right" proper tool.
original Chrysler code reader and the knowledge to use it means he can sort problems, that's why he has a backlog of people wanting his services.
 

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Remember when the door is open the battery is powering something like 9 interior lights
 

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original Chrysler code reader and the knowledge to use it means he can sort problems, that's why he has a backlog of people wanting his services.
I wasn't having a go matey. :) I was just pointing out that with the old Jeeps, there is no piece of kit that will work other than a DRBIII especially when it comes to recoding fobs (which seems to not be the issue here anyway). Believe me I tried, tried and tried! If he has a DRBIII then brilliant. :) Wasn't poo-pooing him at all, I just wasted a lot of time going to people that were "gurus" and "knew everythign" and "could definitely fix it" only to find that no matter what kit they had, it wouldn't work. Eventually found the bit of kit that would work, but no joy with finding someone with it.
 
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