Under hood tidy up/ wiring connector identification

[trevbeadle]

Am trying to tidy up loose wiring connectors under the bonnet. Can anyone identify what this one is please?


and these on the left hand side close to the the alternator


bonnet contact switch? for what?...the under bonnet light or an aftermarket alarm?

Thanks

 

[kentvette]

Can't help with the first two, but the last one is, I believe, the alarm as you suspected, but the factory fitted item. I'm ashamed to say that I have never established what triggers the under-hood lamp! We had a battery drain issue in the early days of ownership and I suspected the hood lamp, so I fitted an inline switch under the hood. Certainly, the "alarm" switch does not have any effect on the under-hood lamp, which seems to be "hot" all the time, but earthed via the hood support.

 

[johng]

Trev, on my 78 the bonnet switch is for the factory alarm. The underbonnet light works via a mercury tilt switch built into the light.

 

[kentvette]

.......The underbonnet light works via a mercury tilt switch built into the light.

After 30 years of ownership, I didn't know that! It looks too basic for anything as sophisticated as that!

 

[trevbeadle]

When I first got the car, a very rusted lamp with no bulb was coiled up with its wires under the left wing. I refurbished it and put it back on the hood. It was live/on all the time so I assumed what I thought was the ‘contact switch’(alarm!) was faulty. The lamp itself looks very basic !!

Is this the factory item?

 

[johng]

It looks like the factory light, here is a picture of mine when I bought the car.



The mercury switch is inside the black plastic piece at the bottom of the light. If you take the light body apart it looks like this. The metal bit in the middle is the switch.

 

[kentvette]

Well I never! Of course, now I'm going to need to have a closer look at mine when the bonnet's open!

 

[Oneball]

Well I never! Of course, now I'm going to need to have a closer look at mine when the bonnet's open!

I’d be crawling under the car and getting the Ms to open and close the bonnet to see if it works.

 

[trevbeadle]

Thank you johng....mine is on all the time when the hood is open!..I didn't think of fully closing the hood to see if it went out, I was too busy looking for a 'contact' switch that the bonnet operated. I think the easiest way will be to dismount it leaving it wired and 'tilting' it by hand to see if the mercury switch works. If not an inline on/off switch maybe the answer!! I will also check the ground through the bonnet stay as mine is missing.

 

[johng]

Trev, if your light is on all the time the bonnet is open then there is nothing wrong with your ground connection. The first photo I posted shows an additional ground wire connected to the left hand mounting screw. This wire was added by a previous owner and isn't standard and shouldn't be necessary. I've now removed it and it works fine.

 

[trevbeadle]

Took the light off and connected it to a remote battery. Hey presto! Light on, put it horizontal, light off! Tilt away from horizontal, light on! + 40 y o technology....That’s magic !

 

[johng]

Just had a look for your other mystery wires. The first one looks like the connector for the brake valve, you ought to get that fitted.



I don't have the wires in your second photo, what colour is the one with the black plug on it? I have a green wire with that style of plug which connects to the idle solenoid, but on my car it comes from the other side of the vehicle. This photo shows the solenoid but you can't see the cable.

 

[trevbeadle]

Johng. thanks. Would that be the brake proportioning valve as shown in the Haynes and on the right front frame rail? I don’t appear to have one of those! Maybe pre75?
The wire is black with a small green stripe, the other light blue. I don’t have any electrical solenoids on my Qjet which was fitted new this year.

 

[trevbeadle]

I had one on the old Qjet but yes, that wire came from the RHS . The selenoid that kicks in and stops the idle dropping when the Aircon cuts in I think?

 

[johng]

Yes that's the valve but it's on the left frame rail below the master cylinder, I've no idea whether some years don't have these but hopefully someone will know. If you're not supposed to have one why have you got the wire?
I believe the solenoid is to increase tickover when the A/C is switched on, have you got A/C? The only light blue wire I've got at the front end is for the indicators and side repeaters, are yours connected?
John

 

[Alben78]

If you need to leave the hood up for any length of time just release the bulb from the bayonet and pull it out a mm or so. The bulb will remain in the socket but will not illuminate. Trev, it looks like you have a car that Bubba has been working on for some time. It would worry me what else had been removed/ changed/ re worked or goodness knows what else. I would invest in the appropriate factory assembly manual to see exactly what the car was supposed to have.

 

[trevbeadle]

Alben78,
my import started life as a Californian 79/80 305 The carburetor and ignition timing were controlled by Chevrolet's new (at that time) Computer Command Control system . The ignition has been replaced with an HEI system with adjustable vacuum advance and the carb with a more modern Qjet that has no electrical connections apart from choke. The engine now is a late 80's 350 crate engine. That unconnected engine wiring harness has now been removed and the engine bay is much tidier. No electrical 'gremlins' appear to exist apart from a surfeit of wiring!

Johng,
I see that now and it does have a cable/plug attached, so its not that one. In fact that connection seems to be part of the cable loom that all the (now) unused CCC loom supplied, so maybe it was for the original ignition .
The indicators/repeaters/sidelights all work as advertised.
I have A/C but the carb seems to cope with only a miniscule drop at idle when it comes in. The ignition/carb has been set up by a specialist and causes no concern.