# '90 pathy voltage regulator for the fuel gauge and temp sensor



## sdwatt (Dec 18, 2006)

Hi all,

I have a dead fuel guage and coolant guage. I understand that this will require a voltage regulator for this. Does anyone have a nissan part number for this? My dealer is unable to locate a part number for this. And while I am at it can anyone tell me where the hell it is behind the dash? 

Much obliged for the help and I wish all you infidels a Merry Christmas!!!


Best regards,
Sean Watt


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## 88pathoffroad (Jun 6, 2004)

You can buy one from Radio shack if you know how to solder wires onto terminals. They cost about $2. What you need is a 8VDC three-pin TO220 type voltage regulator. The stock regulator is located on top of the gauge cluster on the right hand side as viewed from the front. You have to pull the gauges to get to it. Check here for more: http://www.nissanpathfinders.com/Solution2.pdf


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## grantstigers (Oct 11, 2010)

88pathoffroad said:


> You can buy one from Radio shack if you know how to solder wires onto terminals. They cost about $2. What you need is a 8VDC three-pin TO220 type voltage regulator. The stock regulator is located on top of the gauge cluster on the right hand side as viewed from the front. You have to pull the gauges to get to it. Check here for more: http://www.nissanpathfinders.com/Solution2.pdf


Hello 88pathoffroad

I just bought a 91 pathfinder. Temp doesn't work but there is heat. The fuel gauge was reading 1/2 full. I filled it up and the fuel gauge went to empty.
I thought it would be the fuel sending unit. I replace it with used working unit.
Still the fuel gauge read empty.
Reading on the forum I have come across either ground or it could be the voltage regulator. What do you think?
Thanks for your help in advance.
Grant


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## zetune (Sep 16, 2010)

grantstigers said:


> Hello 88pathoffroad
> 
> I just bought a 91 pathfinder. Temp doesn't work but there is heat. The fuel gauge was reading 1/2 full. I filled it up and the fuel gauge went to empty.
> I thought it would be the fuel sending unit. I replace it with used working unit.
> ...


I just had this classic issue on my '90. I bought a replacement regulator from the scrap yard and it didn't work either. As I understand, these things all fail eventually on the Pathfinders. Probably some other Nissans too.

I got an LM117 and made my own regulator. On this datasheet is a sample schematic for a 1.2-25V adjustable regulator.

http://www.national.com/ds/LM/LM317.pdf

You can do some math to find out the right resistances to get 8 volts out, and then discover that you'll never get exactly 8.00 anyways. I used a potentiometer and set it to 8 volts while it was connected to the instrument cluster. Then I realised that the fuel gauge would point right at full when full. and point right at empty when there was still 1/4 tank left. So I cranked up the regulator a bit to make the gauge read a bit higher, Now it points at the letter F when full and when its pointing at the E, its actually pretty close to empty. As a result, when my engine is at normal operating temp. the coolant gauge reads "half" ha ha. which makes no difference to me.

I spent $25 on a nice prototyping board, a project box and a fancy knob. But really, this could be built for way cheaper if you are more resourceful. 

If you want to check the connections at the fuel tank. There is an access panel under the carpet in the rear hatch area. You need to remove the plastic sash under the rear hatch and the 2 rear anchor hooks. (have fun with those). The rear of these trucks is super-prone to rust.

Hope that helps


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## smj999smj (Jan 1, 2006)

Found the regulator at Courtesyparts.com. The voltage regulator is listed under section 248: Instrument meter and gauge. The regulator is #25020 in that section, listed as "regulator." You can either pick one up through them or give your dealer that info and he should be able to look it up. I believe the actual part number will start with the prefix "24866- ." They run in the $40 range.


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## grantstigers (Oct 11, 2010)

Just want to say a Big Thanks for smj999smj for finding the regulator at Courtesyparts.com
However they didn't have one so I got one from the Nissan dealership in Vancouver BC where I live. it was a 2 day wait. Did cost 48.00 but I'm not that great in soldering a new diode which I bought from an electronics place. To many wires to deal with. 

Thanks to other replies regarding the schematics but I just didn't have the time to figure it out. 
I did run out of gas on the highway which was supposed to be a 1 hour trip ended 5 hours. So in saving a few bucks cost me more in the long run,
I installed the Regulator 24866-54A00 . Just behind the left of the cluster. Works perfect and I have the fuel guage working. Thanks to all who replied. 
Grant


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