Stock Radio with aux input

I got a bug to install a factory radio. The original stereo had broken awhile back when my Dad still owned the car and he has installed a new head unit with CD. I was okay with losing CD ability (and picking up tape ability!) as long as I could add an aux input. My Dad had added an input to the original stereo so we knew it could be done but any documentation on the mod was lost so we had to start from scratch. I picked up a radio in great shape from a fellow board member and we got to work.

We were able to power the radio with a DC supply and probe around with the oscilloscope to see where the audio went and where might a good spot to tap our own signal in.

We ended up using the 3 pin connector seen at the bottom of the picture above. Running two wire pairs out of the back of the radio I am able to use a switch to control which input the radio sees (my aux input, or the radio/cassette input).

This should be a short video of the switching in action.

The final install of the switch and radio should happen tomorrow 🙂

Well I had an issue with the left channel dropping out on the radio (unrelated to the aux input mod) so I had to trace the signal back through the left amp and reflowed a few connections on the amp and also the volume control. After all that the left channel seems to be working much more reliably.

Old new stereo

New old stereo

I got the radio installed without much issue. On the driver’s side pop-out (on the left below the radio) you can see a very subtle switch. This is what switches between the radio/cassette and my aux input. On the right in the back you can see the floating 3.5mm jack. Instead of mounting it somewhere I left it as a cable so I can tuck it away if I want.

Also a few of these showed up in the mail today from Amazon. Having the aux input really eliminates the need for cassettes but I think it will be fun to have some in the car.

Fog Lights

Over the past 3-4 days I have been working to install a new pair of fog lights on my MR2. I’ll be adding my final schematic (that went through 3-4 revisions) and some work in progress shots to help those in the future.

On to the pictures!

First up is a shot of the fogs mounted. Mounting was by far the easiest part. I removed a bolt holding the metal bar on the bottom side of the bumper and had to replace it with a slightly longer bolt due to the thickness of the fog light mount.

For the wiring I’ll be attaching a schematic but it consists of one relay and an OEM fog light switch from Paul Sims in the UK. I had several issues getting the circuit right. Part of the issues came from wanting the fog lights to only be able to be turned on when the headlights are on and also the little lamp in the fog light switch.

This is the switch off, and then on (there was just a blank there before)

These lights basically have two modes. When the running lights are on the Koito logo shines through the cover. When the headlights are turned on (and the Fog Light switch pressed) the covers open and the main fog lamps turn on

Here is a short video of them in operation:

I still need to add a fuse at the fog lights and there is one other issue to address.

The covers will only close when the headlights are off and running lights are on. This takes 5-10 seconds. Problem is when I turn off my lights I flip from ON straight to OFF (only passing by the running lights for a split second), this leaves the covers open. I’m working with an EE at work to create a simple time delay circuit that will allow voltage to stay on the lamps long enough for the covers to close. If it gets to be too big of a headache, I might just live with it the way it is 🙂

An electrical engineer at work was nice enough to design and build this little board. It allows a constant +12V to switch in for ~30 seconds after the running lights +12V goes away. This allows the headlight covers time to close when I turn off the lights.

Dead Battery

After sitting for so many years my battery is dead and I would love to salvage it instead of having to buy another.  I have gotten some direction via as to what charger to buy and I hope to be able to recharge and use this battery.  Having one less thing to replace would be great 🙂

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