Radio Woes

[Dolinmyster]

I just bought a Pontiac Parisienne and it a number of small issues with it. The main one is that the radio is completly missing. I just was wodnering if anyone knew what connectors went to what. As much as I love to listen to the sound of the engine, i still enjoy listining to the radio. Also the gas gauge does not seem to work. What could make that happen, and how can it be fixed. I'm new too working on cars, spent six years selling computers and working on them. Was always too afraid to work on my own car. But now am starting to become very interested in fixing my own vehicle. Any help and advice would be very nice indeed. Thanks.

[MagicRat]

Okay, I will assume that whoever removed the old radio did not disconnect it at the connectors, but simply cut the wires, right, and I assume the old speakers are still in place, right?

So right now you have a bundle of old wires behind the dash? Without a wiring diagram you can figure out what goes where.....

Well, likely you have 4 speakers, so 4 wires are speaker negative and 4 are speaker positive.
Dive into the trunk and look at the existing rear speakers. Take note of the colour of wires that go to the speaker. See if the speaker terminals are labelled '+' or '-'. If yes, then you know which are the positive and which are negative speaker wires.
Now, behind the dash, if you are lucky, you should see 4 sets of wires with the same colour wires. Obviously each 'set' of wires goes to each of the 4 speakers.
Now, get an old home stereo, blaster etc. Temporarily hook up each set of wires to the stereo's speaker terminals, one at a time. The car speakers should come on, one at a time. You can then label their location, right-rear, left-rear etc. Put a little masking tape flag on each wire set.

If you are not sure which is the '+' or '-' wire, try hooking up each speaker, listen to it, then reverse the wires. If the speaker is hooked up backwards, it will sound worse than when its hooked up properly, so by careful listening, you can work out which speaker wire is '+' and which is '-'.

So with the speaker wires labelled, use a 12 volt test light to identify the remaining wires. Clip the test light wire to a chassis ground ( metal part of the car body, etc) and backprobe the remaining wires with he ignition key off. If you find a power coming from a wire, then label this one 'memory'.

Now turn the ignition on and look for another wire wire that has power only when the ignition is on. When you find it, label it 'main power'.

Now, turn the headlights on, and probe the remaining wires. If you get another wire that has power, this is probably the dashboard light dimmer. You will find the test light will dim as you dim the dash lights.

Finally, clip the test light wire to the main power wire and probe any remaining wires. When you get a nice bright light, label that wire 'ground'.

Are there any remaining wires? It's possible one of those is for a power antenna. If you have a fixed antenna, then do not worry about it.

Now you should have all the wires required to hook up a new stereo. I would suggest get an aftermarket one. It will probably sound better than an old, stock GM radio. But you may have to do a bit of research to find one that fits the big hole left in the dash, unless you are comfortable with cutting and fabricating a new way to mount the stereo.

As for the gas gauge...... where does the gauge needle point.... to F or E?
If it's at F, it indicates the wire going to the sender unit in the tank is grounded, if it's at E, then the wire has an open circuit (dirty or broken).... or the sender unit is broken.

If there is no obvious wiring problem then the gas tank would need to be dropped and the sender unit removed and tested. Also the float would need inspection to make sure it has not 'sunk'.
It's not a tough job, but it's not recommended for beginners as you are fooling around with gasoline etc.

[Dolinmyster]

Originally Posted by MagicRat

As for the gas gauge...... where does the gauge needle point.... to F or E?If it's at F, it indicates the wire going to the sender unit in the tank is grounded, if it's at E, then the wire has an open circuit (dirty or broken).... or the sender unit is broken.

If there is no obvious wiring problem then the gas tank would need to be dropped and the sender unit removed and tested. Also the float would need inspection to make sure it has not 'sunk'.
It's not a tough job, but it's not recommended for beginners as you are fooling around with gasoline etc.

It was stuck at E. I did put more gas in there and it seemed to come to life. Was at 3/4 tank then back down and would wobble all over the place.

[MagicRat]

Originally Posted by Dolinmyster

It was stuck at E. I did put more gas in there and it seemed to come to life. Was at 3/4 tank then back down and would wobble all over the place.

It's likely the sender unit in the tank is bad, espe0cially the float, which may be partially saturated with gasoline so it is starting to sink.