The Mitsubishi Pajero Owners Club®

[cavecommander]

91.. mk ii.. 2.5 paj..

i have no drive lights at all.. its not the bulbs or anything connected with the dash panel.. had it off and checked em all..

been under the front and had the actuator off.. greased and made sure its working freely.. the diaphram and pipes are okay so is the vac tank..

there seems to be a permanent suck from the diaphram side that would pull the rod out.. i assume this would be the position for 4 wheel drive and the freewheel is permanently engaged.. ??

if i am right the only incorrect part would be no freewheel when in 2 wheel drive mode.. when in four wheel drive mode everything would be correct.. ???

in short i dont seem to have any electrical functionality at all.. but the truck seems to be doing what it should be doing when the drive select lever is moved about.. there are no untoward noises or such and four and two wheel drive seems to be selected and de-selected..

correct me if i am wrong but the select lever seems to be purely mechanical and directly operates the transfer case bits and bobs.. there are variouse switches which tell the ecu what dash light to switch on and which of the two servos to energize and move the freewheel clutch lever in or out.. one way for two wheel drive and the other way for four wheel drive.. freewheel clutch unlocked or freewheel clutch locked..

i am having problems finding a wireing diagram and also which fuse might be blown and where the ecu is..

i am also preparing for a worse case scenario.. the need to replace an expensive ecu thingy.. which to be honest apart from working some fancy dash lights i think cound be bypassed alltogether..

those two servos could be manually switched as and when required and i can live without the lights telling me something i should already know..

or being as everything i read seems to say a permanent 4 wheel drive system is the best.. why cant i just leave it in 4 wheel drive mode.. would this affect fuel economy much or wouldnt it..

thanks for any input..

trog

ps... i think i have found the fuse that feed things..

[Google]

[cssuk]

http://4wd.blogeasy.com/article.view.run?articleID=318776



try that

[nikb2005]

that link provides a very indepth fault find and solution, nice one !

i have a similar age 2.5td with no lights at all.

on my shopping list i ordered a pack of bulbs as i though that is all it would be, but still yet to fit them, so fingers crossed !

nik

[vmaxsnoopy]

On top of the front axle diff housing is an electrical pressure swith that connects to a multiplug on the O/S/F inner chassis rail. This is responsible for the electrcal feed to the warning lamps. Might be worth checking the multiplug contacts or the switch itself. It just screws into the casing.

[PG Scooby]

What ECU do you mean? - The 2.5 has very basic control over the gearbox only. It's not until 2000/2001 that the diesels had any sort of engine ECU so don't worry there.

And also try a couple of new bulbs to rule out that - get them from Mitsi, they're only £1 for a pack of two.

[cavecommander]

"What ECU do you mean?"

exactly.. i assume there is one cos it gets mentioned a lot.. i havnt actually found one.. the link posted i have been thru in great depth.. in fact i think i have a pretty good idea what piece does what and why it does it..

i have had the dash panel out and checked all "twenty" odd plus bulbs.. the only blown one was the "D" in the auto box indicator line up..

i cant really see any need at all for a computer controled piece of wizardry.. except to flash warning lights and such on the dash if all the censors are not in the correct place..

the vacumm side of things is very simplistic.. just two pipes one going to either side of the actuator diaphram each pipe is connected to a solenoid switch/tap which opens and closes them accordingly.. the rod either gets pushed in or pulled out.. the solenoids are connected to a single vacuum source pipe.. the vac tank simply acts as a reservoir and just connects to the vacuum source pipe.. the vac tank could well be up in the top but i assume gets bunged underneath near the axle cos of lack of under-bonnet room..

http://www.cavecom.com/pics/vac.pdf

the oft mentioned actuator switches sole function on the top of the axle seems to be a warning light thing.. if it dosnt match the selector lever postition a dash warning light gets flashed..

in fact all the complications seem to be warning/indicator light connected,.. either my dash lights are not all working or they are flashing.. he he

most of the sensors that go wrong are warning/indicator light connected and from a functionality point of view arnt needed..

the way i see it one sensor on the top of the transfer case that tells the front axle whether or not to be in freewheel mode or not would do the job.. the rest is just pretty looking flashing light junk.. okay when new but a pain in the ar-se when it all starts to go wrong..

all this to get a user selectable 2 wheel drive option which seems to be mostly being dropped in favour of a permanent less complicated four wheel drive system in newer vehicles..

i dont mind fixing mine if i have to.. but dont much fancy spending big money on some ecu unit if such a unit exists..

my two alternatives would be..

rig the front axle freewheel to be manually switchable as required.. not that much trouble to flick a switch.. and far easier than getting out and doing it with a spanner as used to be the case.. he he

or just use the permantent four wheel drive option and leave the front axle in the freewheel locked mode..

the bottom line here being.. do i really need two wheel drive and the added complications of a switchable freewheel front axle it brings plus the fancy lights or will things just work hunky-dory without em in a permanent four wheel drive mode..

trog

[PG Scooby]

Maybe I didn't explain myself clearly enough.

The only ECU your model (possibly) has is one that monitors and adjusts the timing of the gearchange in the auto box. There is no engine or other ECU to worry about.

(I say possibly because 1991 is around the time the gearbox ECU was introduced.)

Your problems are no doubt electrical (rather than electronic) or mechanical. If you remove the dash pod you will be able to check for voltage on the bulb holders with the ignition on to prove if the problem is earlier in the system.

It will be an equally straightforward process to trace the switches on the various parts of the 4wd selection mechanism.

You are obviously capable when it comes to the process of following the logical order of the working of the parts, so keep us informed!

[cssuk]

my 4wd (1992) has 2 ecus one for the main system that controls the solenoids under the radio and one in the rear wing to control the locking diff the ecu may/maynot just control the lights but something stops you from selecting low even stationary unless in neutral

[cavecommander]

i have conflicting information scooby u explained yourself perfectly.. i think the problem is most definitely not mechanical..

i think its also right at the begiining of the chain so to speak.. i have power at the fuse.. that could be considered the real beginning.. lacking a usefull 1991 wireing diagram i dont knoiw what comes next..

the only usefull diagram i have come across has a 1999 date on it.. this one defintley shows a central control unit that is for the dash lights and two wheel four wheel control system.. it tells what lights to light up and controls the two solenoids and such..

on a sport (later vehicle) its on the right side of the drivers footwell.. on my 91 paj it might be under the radio.. u say it hasnt got one "possibly"..

electrical activity at the dash panel would light bulbs.. i have no bulbs lighting.. i have no voltage change at the solenoids when the selector lever is moved.. i am pretty certain that electrically the system is dead..

after the fuse comes the ecu if there is one.. if there is one and its dead checking other hard to get at voltages at variouse places is pretty much a waste of time..

i have found an empty white socket right under the fuse box in the drivers footwell which causes me to wonder what might plug in it..

i have looked in the haynes manual and googled about in an attempt to find the information i need.. i only ask none straight forward questions in forums as a last resort.. from experience if my googling hasnt produce the answer.. the answer isnt to be found.. or at least not easily.. he he

the internet might be a wonderfull place but for every bit of good information there are ten bits of bad..

one guy might well be the most knowledgeable dude in the world.. but when u know enough about the subject to know he is the one with the right answer u dont have to ask the question in the first place..

does my paj have an ecu unit to control the functions i am talking about.. if it does where exactly is it..and how can i get at it.. ???

something stops u selecting a gear unless the brake is pressed.. something stops u locking the center dif as has been mentioned.. something stops u starting the engine unless in park or nuetral.. something stops u even taking the key out unless in park..

sounds like some kind of electronic brain at work here.. praps mine is only half dead just like my real one.. he he

trog

[cssuk]

mine 1993 car regis as a j (check ur seatbelt labels) is under the radio along with the bleeper for reverse the wifes which is a 91 swb is under the glovebox along with the ecu for the glowplugs most elec problems on these seem to be caused by cackhanded radio installs or towbars where people hack away to get a connection best bet go to a scrappie and look in a few my ecu and the wifes is about the size of a ciggie pack and silver whether it is infact an ecu or just a low voltage relay am unsure but the system will only work under certain conditions and of course there is the startup self check which suggests it is a logic controlled ecu

[cavecommander]

looking at this admittedly 98 diagram it seems the pair of solenoids that control the front axle actuator are entirely independent of the ecu device..

they seem to be powered straight from the fuse and activated by the 2/4 wheel drive detector switch on the transfer box..

it seem my idea of all that is needed from a functional point of view is exactly correct..

the rest is about warning lights.. in some cases anti lock brakes.. and all the things u cant do for other safety reasons..

the ecu if fitted plays no part in the operation of the front freewheel hub at all..

nice to have a theory proved correct..




trog

ps... the 2/4 switch on the transfer case seem to provide a simple on or off earth.. if someone a little wiser than me could explain the part played by the diode in the circuit it would be appreciated.. would it possibly cause the second servo to reverse and so open one side of the actuator diaphram to atmosphere pressure..

[cavecommander]

had another go at the problem today.. cant say as i got anywhere much.. except to find out there is no power being fed to the solenoids at all..

i did discover that the default solenoid position with no power going to them (plugs removed) is the dog clutch engaged mode or four wheel drive mode..

a simple swop around of the two colour coded pipes where they join the solenoid reverses the situation and puts the dog clutch in dissengage mode or two wheel drive mode..

feeding power to the solenoids also results in a dissengaged dog-clutch or two wheel drive mode..

the manual switching does seem a feasible idea if i choose not to go any further with the rest of it..

at present i have left the clutch engaged and will use permanent four wheel drive for a bit..

at a later date i will swop around to two wheel drive and see if there is any notcable difference in fuel economy..

trog

[ugurak]

Hi, for the rear lights not to work would mean the fuse is blown or the power supply wire from this fuse is broken. I'm having a more or less similar problem. Found the coils of both solenoids open and waiting for replacements
I'm working on a 1998 Pajero Evo automatic Transmission. I can't get a ground to the signal when I move the select lever from 2H to 4h so I reckon my 2wd/4wd detector switch is faulty or it's wiring broken. Problem is I can't find a good diagram to help me locate this switch on the transfer case. Any help there appreciated.

[cavecommander]

old thread been resurrected this.. interesting reading my own posts from a while back.. he he

i now have my front axle dogclutch on a simple dash mounted on off switch..

if i want four wheel drive i switch it one way if i want two wheel drive i switch it the other way..

the drive select lever takes care of the rest..

i still have no lights and i have an extra low ratio two wheel drive option i never had before..

it all works perfectly.. and none of the other half dozen  sensor switches are needed.. they are mostly to do with the lights and switching the front axle in and out which i now do manually with my switch..

trog

[ugurak]

Hi,
   Well, since I have isolated the causes, I'll try rectify as per the wiring diagrams. I've got some time tomorrow and will have a go at finding the 2wd/4wd detection switch. Thanks and Happy New Year.