Question: 1993: Running wire From Engine to Compartment behind pass. seat

[SilverFoxDan]

I have a 1993 convertible and looking to run an extra multi-wire cable from the engine compartment into the passenger compartment.
I know there are cable runs behind the battery but, is this the best place to get through the firewall?

I know there is a cable run that goes through the drivers side rocker panel all the way to the back, probably for the rear lights... etc. (goes to front of rear wheel well). Is there any cable access from around the rear axle up into the pass. compartment?

Thanks!

 

[DonB]

I believe you can get access through the storage box behind the drivers seat. On my '90 the ABS pump assy. is located below it and there is a cover in there. But...using entry points in the rear open you up to C O entry.
You didn't say where in the passenger compartment you wanted to route the cable too or for what use. Personally I'd drop the drivers side lower bolster and come through the firewall behind the battery area. The factory uses that area and it seems to be a good spot. From there you can pretty much go anywhere with it.

 

[SilverFoxDan]

I am going to the right hand cargo compartment behind the seat (where the Bose radio receiver sits on the '93 convertible)

I will be installing an Arduino based radiator fan controller in that space so I need to get and send engine data + car speed info. to it. Thanks for the tip about the drivers side ABS compartment... you are right about holes in that area and using caution.

I have to lower the drivers side cover anyway to adjust a finicky high beam switch so I will look at all the options and decide which one is best. Thanks!

 

[DonB]

I am going to the right hand cargo compartment behind the seat (where the Bose radio receiver sits on the '93 convertible)

I will be installing an Arduino based radiator fan controller in that space so I need to get and send engine data + car speed info. to it. Thanks for the tip about the drivers side ABS compartment... you are right about holes in that area and using caution.

I have to lower the drivers side cover anyway to adjust a finicky high beam switch so I will look at all the options and decide which one is best. Thanks!

I have the same issue with my high beam switch. I think the actuator rod bends.
Any advice

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[SilverFoxDan]

I'll let you know what I find. Panicked a bit when I took the car out of the garage for annual inspection when it would not switch. Saw a note somewhere that if you put the steering wheel all the way up, it can free up the switch which worked for me but I don't like having to put excessive pressure on the cruise control lever to switch which I do now.

 

[DonB]

I'll let you know what I find. Panicked a bit when I took the car out of the garage for annual inspection when it would not switch. Saw a note somewhere that if you put the steering wheel all the way up, it can free up the switch which worked for me but I don't like having to put excessive pressure on the cruise control lever to switch which I do now.

I'm afraid of forcing it too. There's a lot of stuff in there to take apart.

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[Hib Halverson]

I am going to the right hand cargo compartment behind the seat (where the Bose radio receiver sits on the '93 convertible)

I will be installing an Arduino based radiator fan controller in that space so I need to get and send engine data + car speed info. to it. Thanks for the tip about the drivers side ABS compartment... you are right about holes in that area and using caution.

I have to lower the drivers side cover anyway to adjust a finicky high beam switch so I will look at all the options and decide which one is best. Thanks!

Be careful with using some other device to control the cooling fans.

They are already controlled by the engine computer based on engine coolant temperature, vehicle speed and HVAC pressure.

 

[gmjunkie]

Be careful with using some other device to control the cooling fans.

They are already controlled by the engine computer based on engine coolant temperature, vehicle speed and HVAC pressure.

I agree!~~!!

 

[DonB]

I'll let you know what I find. Panicked a bit when I took the car out of the garage for annual inspection when it would not switch. Saw a note somewhere that if you put the steering wheel all the way up, it can free up the switch which worked for me but I don't like having to put excessive pressure on the cruise control lever to switch which I do now.

Hi SilverfoxDan. I didn't realize till now that this was for a fan controller. Totally NOY necessary!!!!! Check out this kit from Corvette Central #244074. It consists of an additional temp switch that mounts in the water jacket plug in the left cylinder head between cylinders 1 & 3. Easy to get to. There is a two wire harness that then gets spliced into the control wires going to the fan relays on the side of the radiator housing. it "will" activate the fans at 195* and turn them off at 180*. Instead of the ridiculous 230* as the factory has it set. I also have a 160* thermostat installed too. She runs nice and cool on hot humid days with the A\C on,here in Chicago. Plus she's a happier engine. Check it out!! It's only $39.99 and IT WORKS like a charm and no need to breech the cockpit.

Also per our previous conversation, my dimmer works great with the wheel tilted up, but when I have it tilted most of the way down, where I like it to drive, it doesn't quite "make" it "click." I have a new actuator in the column so the rod may be bent,....unless the switch is adjustable. I'll check the FSM. 'Cuz I know someone will suggest that.

Don

 

[SilverFoxDan]

Thanks all for your comments on the fan controller and I hear and agree with your cautions on messing with the design. Done correctly, the ECM and its supporting systems stay in control (to the limits of their design) and they have no idea there is an extra system installed. I'll let you know how it turns out. Thanks DonB for the tip on the kit.

A combination side note about my electronics background as well as why I fell in love with the C4 Corvette is the CAD-CAM company I worked for (Applicon) designed and built the computer systems (about 800K a pop) that GM used to design much of the C4. Really cool to see the "virtual" car before they put her together. Before I retired, I also did some design work and repaired electronic control systems that were installed on Navy ships (sonar weapons and gun control) so "careful" is in my nature.

 

[SilverFoxDan]

I believe you can get access through the storage box behind the drivers seat. On my '90 the ABS pump assy. is located below it and there is a cover in there. But...using entry points in the rear open you up to C O entry.
You didn't say where in the passenger compartment you wanted to route the cable too or for what use. Personally I'd drop the drivers side lower bolster and come through the firewall behind the battery area. The factory uses that area and it seems to be a good spot. From there you can pretty much go anywhere with it.

Update on the wire access issue:
Dropped the Drivers Side (DS) bolster and I have to compliment the GM engineers in sealing up the wire access area really, really well. Fact is, on the '93 convertible, they installed a giant firewall electrical connector plug totally over the access hole. I couldn't snake a needle through it if I tried. There is a 7/32's hole for the cruse control vacuum hose (goes to a module on the brake pedal) but I will leave that one alone as well.

Best bet is the ABS pit behind the drivers seat. It is easy to get to the Bose receiver compartment (where I need to go) form there as well. As I mentioned, there is unrestricted access from the back wheel well, through the DS rocker panel going up front where it exits below the battery (the ABS cable runs that way now). I also have to run a drive shaft speed sensor signal to the Bose pit so access at this point is ideal. I have to know vehicle speed because I have read that the C4's ECM shuts off the fans above 48 MPH (turning fans restrict air flow above this speed). I will know more about this when I test it and will let the ECM have its way if true.

Thanks DonB for the tip!

 

[SilverFoxDan]

I'm afraid of forcing it too. There's a lot of stuff in there to take apart.

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While looking at the wire/firewall issue, I checked my headlight switch setup from the lever to the switch. There are a few variables in this setup including; the switch/mounting, the metal actuation rod and the cruise/headlight beam control lever. By the way, the switch bracket normally holds this switch solidly in place.

What I found on mine was, FIRST and FOREMOST, the metal rod "bottoms out" the switch as it should in any steering wheel position. Any fault in mine lays in the switch (and the design)

To test this:

1. manually push in the switch to test it by pressing its top (don't use the cruise ctrl lever). You will know if it switches/snaps to the other position by feel and sound. The switch-over on mine was just before it bottomed out and not before.

You may know this already but these switches have a decent amount of spring pressure because you are actually "cocking" the switch contacts so they snap to the other position. Electrical contacts need this snapping action to minimize arching in high current situations.

2. Then use the Cruise/headlight steering wheel lever with the steering wheel in your drive position and apply pressure until the switch clicks (or not if it is not working) then, while holding the lever in that position, press down on the switch to to see if it has bottomed out (can not go any further toward the firewall). If there is ANY slack and the switch top moves, you need to check for play in the switch mounting, the rod or (God forbid) the Cruise/headlight lever. If however, the switch has bottomed out, any problem in a lack of actuation is the fault of the switch.

Why does putting the steering wheel all the way up work better? My guess (since the switch bottoms out in any position) is that the angle allows for more rod speed and this has a better chance of putting the switch cocking mechanism over the "click" point.

This is exactly the same setup that my '85 Pontiac/GM Firebird had and I hate it. Why? because they skimp on the Cruise/headlight lever mechanism which is the first thing to suffer as the car ages and these things are not cheap.

All that said and since my switch bottomed out I lubricated the slide that the switch cap slides on (silicone spray) and things are better. I may look for a new switch although there is always the chance that a new switch will have more spring pressure and the 22 year old cruise control lever my take exception to having to do more work. It's like the story of the guy who just replaced a head gasket which promptly blew out his old and tired piston rings. Not that that ever happened to me one dark November day with my 85 Firebird...

Good luck!

 

[helphos]

High beam switch FIX

While looking at the wire/firewall issue, I checked my headlight switch setup from the lever to the switch. There are a few variables in this setup including; the switch/mounting, the metal actuation rod and the cruise/headlight beam control lever. By the way, the switch bracket normally holds this switch solidly in place.

What I found on mine was, FIRST and FOREMOST, the metal rod "bottoms out" the switch as it should in any steering wheel position. Any fault in mine lays in the switch (and the design)

To test this:

1. manually push in the switch to test it by pressing its top (don't use the cruise ctrl lever). You will know if it switches/snaps to the other position by feel and sound. The switch-over on mine was just before it bottomed out and not before.

You may know this already but these switches have a decent amount of spring pressure because you are actually "cocking" the switch contacts so they snap to the other position. Electrical contacts need this snapping action to minimize arching in high current situations.

2. Then use the Cruise/headlight steering wheel lever with the steering wheel in your drive position and apply pressure until the switch clicks (or not if it is not working) then, while holding the lever in that position, press down on the switch to to see if it has bottomed out (can not go any further toward the firewall). If there is ANY slack and the switch top moves, you need to check for play in the switch mounting, the rod or (God forbid) the Cruise/headlight lever. If however, the switch has bottomed out, any problem in a lack of actuation is the fault of the switch.

Why does putting the steering wheel all the way up work better? My guess (since the switch bottoms out in any position) is that the angle allows for more rod speed and this has a better chance of putting the switch cocking mechanism over the "click" point.

This is exactly the same setup that my '85 Pontiac/GM Firebird had and I hate it. Why? because they skimp on the Cruise/headlight lever mechanism which is the first thing to suffer as the car ages and these things are not cheap.

All that said and since my switch bottomed out I lubricated the slide that the switch cap slides on (silicone spray) and things are better. I may look for a new switch although there is always the chance that a new switch will have more spring pressure and the 22 year old cruise control lever my take exception to having to do more work. It's like the story of the guy who just replaced a head gasket which promptly blew out his old and tired piston rings. Not that that ever happened to me one dark November day with my 85 Firebird...

Good luck!

I had the same problem, but I had an extra steering column to play with! The high beam switch has oval holes which allow you to loosen and move the switch a little. I did that and solved the problem. I hope these pictures are useful.

 

[SilverFoxDan]

I had the same problem, but I had an extra steering column to play with! The high beam switch has oval holes which allow you to loosen and move the switch a little. I did that and solved the problem.View attachment 22155View attachment 22154View attachment 22156I hope these pictures are useful.

Thanks for the details and the pictures! I actually ordered a new switch, 11 bucks and change on eBay, as a future spare and will take a hard look at my original switch before I change it.

Holly crap these switches have a lot of spring/snap pressure. It's a prehistoric, bruit force design that has existed since the late 70's and I am trying to calm the engineer in me from tearing it all out and replacing it with an electronic switch. Put away those Power MOSFET's... step away from the dashboard!

 

[hcbph]

First time I've seen that but looks like there's adjustment in those 2 screws on the top side. Can it be adjusted? Maybe slot the holes a little more if needed?

 

[Gene D]

I had the same problem, but I had an extra steering column to play with! The high beam switch has oval holes which allow you to loosen and move the switch a little. I did that and solved the problem.View attachment 22155View attachment 22154View attachment 22156I hope these pictures are useful.

My low/high beam switch was not working. This post helped me. I could not find screws on my 1993.
If I pulled the lever, the switch would not throw.
I held the lever toward the driver, and a little extra push on the switch itself would make it work.
I found if you held the lever toward the driver, and pushed the switch in at the same time, the rod would come out of the socket.
I cut a little piece of sheet metal (about a 1/4" dia.)and I put it in the socket. I then pushed the switch, and put the rod back in with the sheet piece under the rod end.
The lever now works the switch as it should.