How to: Hard wire radar detector into E30

[Kepes 231]

Hey team,

Today I went about hard wiring my Valentine One into my E30 as my cigarette lighter is a bit corroded and didn't make good contact with the socket. Also I don't like people knowing I have a radar detector and this keeps it pretty out of sight from people around.

This also works well if you use your radar detector in different cars as it can be easily disconnected and the wire easily hidden.

It's relatively easy, took me around 40mins.

What you need:
Any hardwire cable with an RJ11 connector. I bought one from trade me because it was only $22, and saved me having to make one.
T-tap connector or quick splice connector. Ebay is good for the T-taps (more about these later)
Small phillips screwdriver
Multimeter or 12v test lamp
Pliers
Wire stripper

Here's everything I used


Start by removing the check panel. If you wiggle/pull it enough it'll come free. There are two tabs holding it on both the top and bottom. Some people use a flathead screwdriver but it's not needed.

Pull the wire/socket off of the check panel and you'll be greeted with this (excuse my long, almost lady-like nails)


Then remove the 4 phillips screws. Be careful as these are really small and easily lost. I now have just 3 screwed in, I lost the other one down the side of the seat

Here's what it should look like


Now use your multimeter to find ground and the 12v supply from the small pins.
Each one has a number, for me ground was pin #9 (brown wire) and the 12v which only turns on when the key is in was pin #23 (one of the purple and green wires).
This will vary between different E30's so check first. I believe most pre-facelift E30s will be the same as mine, but check.

Once you've established which wires you are going to want to take power from, use either your t-tap or quick splice connector.

On the left is the quick splice connector and on the right is the T-tap. Even though the one on the left looks more like a 'T'. Anyway, I had both but decided to use the T-tap because if I ever want to remove the hard wire, it is much easier with the T-tap.


Put the wire through the tap and use pliers to close it. It will stay shut and break the insulation just enough to draw power.


Both wires tapped


Next you'll want to prepare the hard wire. The one I bought had a ring connector on one end and a spade sonnector on the other. I needed them both to have spade connectors.


I stripped the ground wire back and attached another spade connector like that on the positive wire.

Then it's just a process and connecting the spade to the t-tap


Next, test for 12v (make sure the key is in and turned one step). I wasn't getting the 12v at first so I used the pliers to squeeze the t-taps a little more and wa-la. 12.24v


To get the RJ11 connector through to the windshield, push the socket out through the area around the rear view mirror, where there is some flexible rubber. You can see there is already a small gap there



Push the wire through the gap and try your best the fold the wires so they'll sit nicely behind the check panel. It took me a few tries before the check panel would sit flush/fully in. Notice the fuse holder on the wire. It has a 2amp fuse. Make sure you use/make a wire that includes a fuse, you don't want your V1 blowing up!


Put the plastic cover back around the wires and check panel socket, reconnect the check panel and put it in place.

The wire which comes out to the windscreen can be easily pushed back into the check panel area for when you're not using the radar,
rather than just having a stray wire hanging down your windscreen.

Try your V1 or other radar detector. If it chirps, smile. If it blows up, don't blame me.

Edited February 2, 2015 by Kepes

[handgrenade 189]

Nice post ! Well documented. Personally not a fan of t clamps but they are the easiest. Proper solder and heat shrink is best but a lot more work .. Especially if working inside the car !

[B.M.W Ltd 950]

Where did you get those "T" connectors from Toby ?

[Kepes 231]

Where did you get those "T" connectors from Toby ?

Ebay. These ones to be exact

I had a look around locally and could not find them. Once I tried Jay Car with no luck I knew ebay would be my only option. However those quick splice connectors I did see at Super cheap auto and Jay Car

[handgrenade 189]

Yeah jaycar sell only those budget T splices

[actletpone 43]

Tidy job!

[duvey 245]

Nice writeup! Might have to get around to this at some point.

[_ethrty-Andy_ 2122]

i wonder how much power this curcuit can handle