Install a Thermometer in an Old Car [UPDATED]




About: Italian maker, law student, DIY enthusiast. I make lots of projects, I fix lot of stuff and I like to save and reuse materials taken from broken stuff.

Hi everyone!
In this i'ble I will show you how to upgrade your old car (mine is a 2001 Fiat Panda Young) with just 3$ and less than 30minutes.
As you can see in pictures, my car is an old model, so it has just the basic instruments indicator like speed and fuel level. So I decided to add a thermometer also because both in winter and summer my girlfriend, while she is "freezing or melting", uses to ask me "how many degrees are there?!".
I simply turned on my pc, logged-in in my favorite online Chinese electronics website and searched for some cool and cheap thermometer!

This is a VERY simple project but I took a lot of pictures to make all more understandable. ;)
UPDATE - In the last photo you can see my actual analog thermometer. You can read about it in the last step.


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Step 1: Materials & Tools

-digital thermometer (3$)
-piece of plastic from the junk (also paper or cardboard works perfectly)
-your dash panel


-marking pen
-glue (I used vinavil and attack)
-nylon probe puller

Step 2: Choose the Place for the Display

The display of the thermometer measures 4,5cm x 2,6cm so I had to find some cool place where I could put it.

I found 4 possible places;
-one at the left of my steering wheel (occupied by the lights direction
-one at the right of my steering wheel (occupied by the car lighter),
-one under the fuel level indicator,
-and one (my choice) at the right of some car functions buttons.

Step 3: Remove the Dash Panel and Prepare the Thermometer

Since, as I have already told you, my car is old, I am the fourth owner; so I removed the black plastic piece (I think it's called dash panel) with the help of a cutter. This because it was attached just with some silicone.

If you have a new car in better conditions I suggest you to use a screwdriver and carefully remove that panel without break or ruin it.
SUGGESTION: if you wrong something and you break a piece don't worry! Go to the local junkyards and ask for it

After removed the small black panel, I inserted the batteries in my thermometer and I compared it with another thermometer to see if it worked right! (ALL OK)

Step 4: Make a Stencil to Test the Hole Dimension

To make all the project as perfect as I could, I decided to make a stencil with the hole of the same measures of my thermometer.

My thermometer measures 4,5cm x 2,6cm.
After drawing the rectangle on a piece of plastic, I cut it and I tried to insert the thermometer.

If the hole is too small, file it and re-test again.

When the hole is perfect you can use your stencil and with a marking pen you can draw the lines on your dash panel.

Step 5: Cut, File, Sand and Glue It

Once you have draw the rectangle you just have to use your dremel and cut following the lines.

File a little everything and try to insert the thermometer. If the hole is too tight, re-file it and check again.

When the hole is perfect you can sand the surface to make all more perfect and cool. (In photo#4 you can see the differences before and after).

Now insert the thermometer in the panel hole for the last time and apply the glue. I decided to put a small amount of attack (strong and fast glue) only at the 4 angles to hold it in place, and more vinavil (strong but easy to remove in future) around the all perimeter of the thermometer.

Step 6: Remove the Dashboard And...FIND MONEY!!

In order to insert the thermometer you have to remove firstly the dashboard.
So I took off all that switch's caps (photo#2) and, with a screwdriver, I removed all the screws.

Than I removed the air diffuser and after removing carefully the fastons (photo#6), I found the pre-existing hole with all the car wiring.

WAIT WAIT WAIT!! 5cents!! I didn't became rich but.. 5cent are better than nothing!! :P or not?!
Anyway... Let's go to the next step!

Step 7: Insert It in Your Dashboard

All we need to do now is let the thermometer's wire pass through the dashboard hole and the wiring hole.

So first of all insert the wire through the dashboard hole. (photo#1)

Than insert the "nylon probe puller" through the wiring hole and let it exit from the hole at the bottom-right. (photo#2: there is a gap that starts at the right of the dashboard and finishes at the bottom of it)

Now take a piece of scotch and wrap the thermometer's sensor so you can pull the nylon probe's end and let the wire pass through that small hole till the bottom of the dashboard.

Remove the scotch and the nylon probe puller and re-insert the air diffuser.

Remount the dashboard, the plastic knobs, the fastons, the screws and go to the next step to secure the temperature sensor.

Step 8: Secure the Display in Place

Apply a lot of attack both on the dashboard and on the dash panel.

Like you did with the sensor, attach a piece of scotch to keep the dash panel in place while it dries.

Step 9: Secure the Sensor in Place

Let the wire pass to the left (see photo#1 and photo#2) and apply a small quantity of silicone.

Press the sensor on the silicone and attach a piece of scotch to keep it in place until it will dry.

Step 10: UPDATE - Place the Sensor Out of the Car

As suggested by some Instructable members, I thought to change the position of the sensor. I also decided to place it out of my car also because I just thought that outside temperature is more interesting than the inside one.

So I just repeated STEP6 removing the dashboard, and I made a hole on the left side, in order let the sensor (and the wire) pass through it.

TIP: I didn't have any power tools with me so I made the hole with a heated screwdriver. It's a quick and useful solution, and as you can see in photo#3, the result is very clean.

Step 11: UPDATE - Secure the Display, the Wire and the Sensor

I finally remounted the dashboard, replacing all the plastic knobs and all the screws.

Than I (re)glued the display in his place, and I secured the wire with glue and insulated tape.

I placed the sensor on the left door's hinge (photo#4/5), and again I used glue and insulated tape.

NOTE: I was able to set the wire in this way because my old car has a wide gap all around the doors. This gap avoids that I cut and break the wire every time I close the door.

Step 12: Enjoy It!!

UPDATE - As you can see in the first photo, I changed my digital thermometer with an older one. The digital one worked perfectly and the batteries were still alive after more than a year, but one day driving to the university I found a water heater on the corner of the street. I stopped nearby, I noticed the analog thermometer and I dismounted it thinking that it would look way better in my old car. After that, I went to the local junk yards to took another dash panel. I cut a round hole in its center, I filed it until the analog thermometer fitted perfectly in it, and I reinstalled everything together as I shown you in this ible for the digital one.

Good job! You have finished!!
Now you can show it to your friends, family and girlfriend!! And you can probably make your car looks newer!! ...mmm ok! just a little bit :P

Thank you for reading my Instructable. ;)
Feel free to comment and ask if you need to know something!


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    69 Discussions


    7 months ago

    there are thermometer that show the internal and external temperature. they have a sensor in the device and the external sensor at the end of the cable. BUT you place the sensor in a wrong place. Outside temperature is the temperature in the shadow not under the solar light or the wind as you drive. It could show over 50 Celsius or more under direct sun light, which is not the normal thing. Most cars have the sensor under the bumper away from wind , sun , or engine heat


    5 years ago on Introduction

    It's cool to upgrade an older model car. I added extra 12v power outlets always on with an override switch to charge my smart phone and accessories. I did the temp thing too before I saw the exact same gage you used.

    4 replies

    Reply 5 years ago on Introduction

    I have a 1996 Nissan XE P/U. I expect to get close to 1m miles eventually. I'm considering replacing the radio with a modern one with blue tooth and gps.


    5 years ago on Introduction

    nice job, I like seeing those kind of improvement. I did an integrated usb charger on my 04 sentra. It was the best upgrade I ever made :)

    2 replies

    5 years ago on Step 12

    I would like to do this but put the temp sensor outside of the vehicle to know the outside temp. Not sure where I would put it though where the motor heat wouldn't affect it.

    1 reply

    5 years ago on Introduction

    I love Fiat Panda!! Se ti va, unisciti al gruppo Ible Italia:

    1 reply

    5 years ago on Step 7

    You should have left the five cents in there, it was literally doubling the value of your car! Hahah, just kidding. Whereabout did you secure the sensor? Need to find somewhere where it won't get warmed up by the engine or cooled down by windchill. Maybe push it through to the wheel arch?

    Nice neat cutting job, by the way. Those plastic panels in cars are normally "blanking plates" where some option extra might go (air con button?). Used to do loads of jobs like this on my old car. Miss it a lot. Have a modern car now with no oppertunities for DIY automotive engineering. :)

    1 reply

    5 years ago on Introduction

    I don't mean to be critical, but...

    Your thermometer is running on two LR44 lithium batteries. It already has sprung locking tabs on left and right to allow it to "click" into place without the need for adhesive. They're designed for release without much effort too.

    You super-glued the thermometer into the cut dash piece, and it looks neat. However, this will be a hassle when you have to remove it again for the batteries!

    1 reply

    Reply 5 years ago on Introduction

    yeah you are right... ;) it have sprung tabs on both sides but i decided to glue it to be sure that it will stay in place wothout problems. are also wrong... ;) i glued it but i will not need to remove it for the batteries! i'll only have to repeat step3 photo2 and change the batteries ;) this because as you can see in step5 photo12 i don't have to remove the thermometer from the dash panel to change the batteries ;)


    5 years ago on Introduction

    maybe an extra cigarette lighter plug would be more functional with today's digital players needing charged? just an idea.