Crafty12

I'm replacing the carpet in my 70 LT1 coupe. I pulled out the LH dash pad the other day to change the bulbs and update the speakers. I have found two wiring situations that I want some opinions on. Are these factory hookups, or something bubba put together.

The first issue I believe has to do with the alarm system. It's a factory alarm car. There is a small wire harness that has 3 white wires and one orange wire. One white to each courtesy light switch in the front of the jam, and one white to a switch under the hood. The larger orange wire has these weird blue terminals on the end, and it was plugged directly into the BAT terminal in the fuse panel. The wires are then bundled up and run to the back of the car with the antenna and other rear end wires. I have a wiring diagram, but it doesn't show this alarm harness.






The second issue is on a different orange and white wire. These wires come straight out of the main dash harness and plug into the brake light switch. My question is about the rider on the wires. Would this have come from the factory like this? The blue vampire clips seem a bit hacky to me.

Easy Mike

Two alarm wires running to the rear go to the alarm switch in the rear panel.

Scotch locks might be factory but probably indicate the capacitor has been replaced at some time in the past.

fly1977

This appears to be correct, I just replaced my harness with new from electric limited and it was the same way with the rider that goes to the bat terminal and if it has speed warning it plugs in to the rider. Good luck

Crafty12

Thanks Mike.

What is this speed warning? I found an orange/black wire behind the dash pad with a black male plastic terminal on both ends, but neither end was hooked to anything.

fly1977

Speed warning is a extra needle in the speedo that you set and when you go past it ,it sounds a buzzer. The wire that powers it plugs into the rider of the alarm or the alarm plugs into it then to the bat terminal of the fuse panel. Not sure of the color of wires without looking at my 69' or my wiring harness .

Crafty12

No need. I definitely do not have a second needle, or the buzzer under the A-pillar. Thanks for the help guys!

redrdstr72

Hi Matt, I'm sure that the blue connectors are aftermarket. When I was a kid, I worked after school in a boat yard and used hundreds of them to splice into a running wire, picking up power for whatever appliance I was installing. My '72 has none of these.

As for the plunger switch under the hood, I noticed the bracket (plunger was missing, right?) when I saw your car last week. This switch/bracket is for the alarm system, notifying when hood security was breached. There should also be plunger switches in each door jamb, below the striker post. These are separate from the courtesy light switches, which should be on the front side of the door jamb. I think earlier cars might have had a combination courtesy/alarm switch, but I could be wrong on this. The factory alarm system had a flasher switch and a relay in the RH storage bin, under the removable tray. This is the same bay that stores the jack. Look there and see what you see. Let us know.

BTW, do I remember correctly that your '70 did not have a key switch for the alarm? It's supposed to be located on the rear facia, centered above the C-O-R-V-E-T-T-E letters.

Hope this helps.

Don

Crafty12

I'm sure that these wires run the alarm, I was curious about how they were hooked into the fuse panel. It seemed like a bit of an after thought, but maybe since it was an option it was treated this way. The alarm runs through the courtesy light switches on the 70, but it runs through the door ajar switches on the 73. Not sure when the change was made.

The hood plunger is missing, but the wire is still there (lucky for me). The flasher and relay are underneath the bins in both cars as well as the horn assembly under the rear driver quarter. The key switch is in the correct location on the 70. It was removed and glassed and painted over on the 73.

Mashman

The wires with the capacitor on the brake light switch wires have come up a number of times. My 72 had the exact same setup, with the same blue connectors.

The only reason I could (and others in earlier threads) come up with is that it's there to eliminate possible radio interference, like the capacitor on the ignition coil, and the blower motor.

I'm guessing that there was a service bulletin, and when someone came in and complained about radio interference when they pressed the brakes, the dealer slapped one of those on.

Modern radios do not suffer from that kind of interference, so since my capacitor was shot anyway (one of the wires fell out), I simply undid the connectors and removed them.

Crafty12

That makes a TON of sense. Never thought about it being a TSB or it being a period correct fix. Thanks! I still have the stock radio, so I'll just leave it alone.

Thanks for all of the help guys!

7T1vette

Those quick-splice connectors and the capacitor are factory installed. That is the gizmo that GM installed to reduce radio noise from the brake switch when activated. It is merely a "pop" filter and they didn't bother to build it into the wiring. My '71 has the same arrangement.

The other (white) wiring and blue connectors don't look familiar to me...but I don't have a factory alarm system on mine.