1988 Pajero 2.5TD Outside Inside Thermometer Repair

[Craig Williams]

the US gauge would come with two one outside, one inside, if you use the second hand Mitsubishi one you already have, you would need two that match the specifications which is 1000 ohms and as temp increases, resistance decreases (you can get ones which go the opposite way).

[awbeattie381]

Thanks mate. The US one sounds simpler and might be a good option for a b'day gift early in the new year...

[Craig Williams]

US Thermometer Gauge

Yes the US Gauge would be easier as it comes with all the wiring needed I would imagine plus instructions I should think. But it is USD 132.50. Plus postage! You could probably fix your existing old Pajero gauge for less, providing the electronic circuitry in the old gauge is still working? The Thermistors are only a few dollars each then you need some wire, like speaker wire would do the job I believe and know how to solder and basic wiring stuff.

[techlegend]

Hi Craig,

I have tried searching for the inside thermistors with No Luck. Also I have pulled out my Circuit and just wanted to see if it powers up before taking to a electrician. (I have checked for busted Caps/Resistors).

Looked up in my Haynes Repair Manual but there is no mention of this 3 gauge cluster.

Previous owner of my Paj has removed the wiring from the 3 gauge cluster so now It only gets power. (By the looks of it)

Any Wiring Diagrams/Help would help greatly.

See below Images from my Pajero Gen 1 1988

[Craig Williams]

IOTG wiring diagram

I will sketch up a wiring diagram for you tomorrow, photograph my sketch and attach it to my further reply. You need a 12V power supply a positive (from ignition "Accessories") and a negative going to earth. You need two wires going to the inside thermistor and two wires going to the outside thermistor (which are not polarised i.e. positive and negative do not matter which way around you wire them). Speaker wires would do the job. There were also two other wires going to the Pod/Combo gauge for the wedge shaped light globe to light up the gauges at night, which is wired to come on when you turn on your head lights. That's four pairs of wires altogether: 1) Power supply to the IOTG, 2) Inside Thermistor, 3) Outside thermistor, and 4) the Light globe. Those are the eight wires coming from the photo in my post on this topic.
Hand sketched wiring diagram to follow tomorrow, good luck, Craig

[Craig Williams]

IOTG Wiring Sketches (my Diagrams)

These sketches below are exactly what I used to fix my Outside Inside Thermometer Gauge (OITG)

FYI I drive an IMPORT 3/11/1988 2.5TDI SWB

Power Supply
+12V Blue White and Black Green (-) Earth (to Chassis)
Inside Thermistor Red and Red White
Outside Thermistor Black and Black White
Light Globe Green White +12V and Black Yellow (-) Earth (to Chassis)

Circuit Board locations of each of my coloured wires, as per my OITG. Turn your one upside down so the four connections are at the bottom of the photo and the next row up only has three wire locations (no need for the light globe earth wire on the circuit board, if you understand what I mean?).
Below is a link from POCUK, for the Thermistors. You could order them over the Internet or I am sure someone like Prime Electronics, here on the Gold Coast, Queensland would have. The one in the link looks different to mine, but probably does the same job TBC.

http://uk.rs-online.com/web/p/products/1912235/

Just reply if you need me to explain further (ignore the rectangular shadow in both photos it is my iPhone)
One last thought, even if you connect the power supply an Error Code "E" will light up until the Thermistors are connected in too. I honestly do not see what purpose the light globe wire on the OITG circuit board fulfils?

[techlegend]

These sketches below are exactly what I used to fix my Inside Outside Thermometer Gauge (IOTG)
[ATTACH]26161[/ATTACH]
FYI I drive an IMPORT 3/11/1988 2.5TDI SWB
[ATTACH]26159[/ATTACH]
Power Supply
+12V Blue White and Black Green (-) Earth (to Chassis)
Inside Thermistor Red and Red White
Outside Thermistor Black and Black White
Light Globe Green White +12V and Black Yellow (-) Earth (to Chassis)
[ATTACH]26160[/ATTACH]
Circuit Board locations of each of my coloured wires, as per my OITG. Turn your one upside down so the four connections are at the bottom of the photo and the next row up only has three wire locations (no need for the light globe earth wire on the circuit board, if you understand what I mean?).
Below is a link from POCUK, for the Thermistors. You could order them over the Internet or I am sure someone like Prime Electronics, here on the Gold Coast, Queensland would have. The one in the link looks different to mine, but probably does the same job TBC.

http://uk.rs-online.com/web/p/products/1912235/

Just reply if you need me to explain further (ignore the rectangular shadow in both photos it is my iPhone)
One last thought, even if you connect the power supply nothing will light up until the Thermistors are connected in too. I honestly do not see what purpose the light globe wire on the OITG circuit board fulfils?

Hi Craig,

Thanks alot for your time, I will try this over the weekend and get back if some thing is required, You are a savior

BTW attached Image is my Ride, 1988 LWB 2.5 TD

[Craig Williams]

Good luck, and I could not see your attachment?

[techlegend]

Good luck, and I could not see your attachment?

I think the office network screwed the upload, This is my Ride

[Craig Williams]

Thanks it worked this time!

[techlegend]

Thanks it worked this time!

Hi Craig,

Thanks to your diagram and bit of elbow grease I managed to get the device to work again,

How ever there is a component which becomes very hot, I have circled it in the Red. Is this Normal ?

Note: I am not an Electronic Expert hence don't know for sure whether this is a Diode or something else.

[Craig Williams]

I do not think it is a diode

If it is a fairly large resistor 62 ohms 2 Watts (which means it gets very hot!).

Can you run it for say an hour or so, to see if it maintains the temperature evenly and remains working? Be ready to turn it off is you smell something bad happening.

[Craig Williams]

For a comparison from Google Images - Resistors

[ATTACH]26255[/ATTACH]
This is just an example only, the real one is 62 ohms 2 Watts
BTW congratulations for getting it working!

[Craig Williams]

IOTG update for my Import Pajero 2.5TD

Just recently I have had to "tap" on the side of the gauge to get it to come back on, if you hit a bump or pot hole in the road. To fix this means remove and "re-soldering" all the joints. One of them must have become a "dry joint" but who knows which one so I shall have to do them all again. It is 27 years old now! I had to do the same to my 1997 Delica's clock. After numerous " taps" which were getting harder as it became more often I finally bit the bullet, removed and dismantled it, and run the soldering iron over every single soldered joint. It is now working again fine. I do not add more solder unless it looks questionable and needed. Mostly just remelt it as smoothly and quickly as you can, so as not to over heat it. Do not do them all in a row. Go in some-what of a pattern but jump from one side to the other to "spread out" the heat sink, so to speak.

I re-soldered all joints on 23/09/15 and now, over a week later, 2/10/15 it is still working fine. Update 1/11/15 a month later and it has not missed a beat.


Here is how I re-connected the wires which come out the back of the IOTG. The white wire connector comes in "blocks" from Jaycar, they are a little bulky but do the job.

[Craig Williams]

Stay tuned for an update as the IOTG started to play up again (1/5/17) and I have removed the 62 ohm 2 Watt resistor (it gets hot and has broken down) and I am waiting for a replacement via eBay (China) to come in the post. I have taken photos 9 which should be very helpful. See page 4.