autopar3000
Well-Known Member
That is so true. It has taken me so much longer than expected to get to this point, I might have gone a little crazy if it didn't work.
Rewiring my EFI Magnum - 1970 Dart Swinger
- Thread starter autopar3000
- Start date
-
That is so true. It has taken me so much longer than expected to get to this point, I might have gone a little crazy if it didn't work.
autopar3000
Well-Known Member
I should also mention that 2 of those relays and 2 of those fuses you see in the relay box are for the headlights. I didn't document any of that because it has been documented on FABO many times, but the voltage improvement to the headlights is almost unbelievable.
Before the relays, with the headlights on and the battery at 12.9 volts I was getting 9.5 volts at the headlight.
Now with the relays, with the headlights on and the battery at 12.6 volts I'm getting 11.1 volts at the headlight.
And this is with all the old wiring and old connectors on the lighting harness, so once I replace that I'm sure I'll be closer to battery voltage. This test was done before I had it running, so it was with the engine off and a battery charger on it. I'm sure when the car is running and the voltage is my car's usual 13.8 - 14.0 the voltage at the headlights would be 12.0 - 12.5. A massive upgrade.
Before the relays, with the headlights on and the battery at 12.9 volts I was getting 9.5 volts at the headlight.
Now with the relays, with the headlights on and the battery at 12.6 volts I'm getting 11.1 volts at the headlight.
And this is with all the old wiring and old connectors on the lighting harness, so once I replace that I'm sure I'll be closer to battery voltage. This test was done before I had it running, so it was with the engine off and a battery charger on it. I'm sure when the car is running and the voltage is my car's usual 13.8 - 14.0 the voltage at the headlights would be 12.0 - 12.5. A massive upgrade.
autopar3000
Well-Known Member
I adjusted the brake light switch so I could put a few miles on the car before totally wrapping all the wires. Just want to make sure it's going to be reliable before I make everything permanent. So, uh, yeah...
What do ya'll think, a little too tight?
This happened on Friday night. I guess the benefit of using GM parts is that I was able to locally source a replacement by by 10 am Saturday morning.
The one I broke was an OEM GM unit, while the one I got on Saturday is a Carquest brand. The OEM piece has very stiff plastic, almost brittle. While the Carquest piece is a softer plastic. I'm feeling better about the Carquest part.
What do ya'll think, a little too tight?
This happened on Friday night. I guess the benefit of using GM parts is that I was able to locally source a replacement by by 10 am Saturday morning.
The one I broke was an OEM GM unit, while the one I got on Saturday is a Carquest brand. The OEM piece has very stiff plastic, almost brittle. While the Carquest piece is a softer plastic. I'm feeling better about the Carquest part.
autopar3000
Well-Known Member
Final updates on this build. I put some miles on the car to make sure everything was good, then I wrapped up all the wires and put some more miles on it last night. Everything works flawlessly... cruise control, ammeter -> voltmeter conversion, headlight relays, and totally redesigned engine bay wiring. But there are a couple of things I wish I had considered ahead of time.
First, the OD light has a dim glow when the light is supposed to be off. The light is turned on by a ground signal from the PCM, but there's a weak ground signal even when the light is supposed to be off. The factory light would have been an incandescent bulb and the weak ground signal wasn't enough to light it up, but the LEDs don't need as much power to illuminate. I should have thought about this because the check engine light did the same thing with my old setup. For the new setup I put the CEL on a relay so the ground signal turns on and off the relay, and it works perfectly (no dim glow anymore).
Second, I didn't consider that the SET/COAST button is a normally closed switch which is powered when the cruise control is on. Because it's normally closed the SET/COAST light comes on whenever I have the cruise on (RESUME/ACCEL is normally open so it only comes on when I tap the button). I thought of a few ways I could make SET/COAST light come on only when I tap the button, but it's not a big deal so I won't bother.
First, the OD light has a dim glow when the light is supposed to be off. The light is turned on by a ground signal from the PCM, but there's a weak ground signal even when the light is supposed to be off. The factory light would have been an incandescent bulb and the weak ground signal wasn't enough to light it up, but the LEDs don't need as much power to illuminate. I should have thought about this because the check engine light did the same thing with my old setup. For the new setup I put the CEL on a relay so the ground signal turns on and off the relay, and it works perfectly (no dim glow anymore).
Second, I didn't consider that the SET/COAST button is a normally closed switch which is powered when the cruise control is on. Because it's normally closed the SET/COAST light comes on whenever I have the cruise on (RESUME/ACCEL is normally open so it only comes on when I tap the button). I thought of a few ways I could make SET/COAST light come on only when I tap the button, but it's not a big deal so I won't bother.
autopar3000
Well-Known Member
Things I haven't done yet:
- Install the CEL. The wiring is all there, I just have to put a hole somewhere and put the light in.
- Install the new headlight switch. My old switch works, but the dome light won't turn on. I like having a dome light, so this will happen soon.
Here's a pic of the engine bay showing the finalized wiring with relay box, cruise servo, etc. I still have to paint my air filter housing and breather, but it's fine for now.
And here are all the buttons wired into the console ashtray. You can see the SET/COAST button is lit up, and the dim glow of the OD button. It's not really possible to see it during the day, but in the picture and at night it's more obvious.
- Install the CEL. The wiring is all there, I just have to put a hole somewhere and put the light in.
- Install the new headlight switch. My old switch works, but the dome light won't turn on. I like having a dome light, so this will happen soon.
Here's a pic of the engine bay showing the finalized wiring with relay box, cruise servo, etc. I still have to paint my air filter housing and breather, but it's fine for now.
And here are all the buttons wired into the console ashtray. You can see the SET/COAST button is lit up, and the dim glow of the OD button. It's not really possible to see it during the day, but in the picture and at night it's more obvious.
DionR
Well-Known Member
Very nice!
tcanin00
Well-Known Member
Where did you get the cruise control buttons from?
autopar3000
Well-Known Member
Back at this again!
In POST 49 I installed the brake light / cruise control cut off switch, and @DionR suggested I get the proper connector for the brake lights from a yard. I grabbed one from a wrecked Chevy Cobalt last summer and just had the perfect opportunity to get it installed.
I had to pull my steering column out because my Borgeson steering box needed to come out, which gave me great access to the brake switch. As usual, I forgot I was trying to document my work and just went ahead and got it done without any pictures. I de-pinned the connector and crimped my wires on to the terminals of the GM connector.
One thing I realized is that the wires that were on the connecter are pretty small, probably 18 awg. I'm thinking that the cars that use the switch and connector probably have a relay for the brake lights, rather than have all the power running through the switch.
Has anyone here put their brake lights on a relay?
TT5.9mag
Two atmospheres are better than one
Headlights yes but never brake lights. I would imagine those bulbs pull less than 2 or so amps when lit and only while braking. No need for a relay. The 18awg should handle that just fine, especially with a short, good, ground.
autopar3000
Well-Known Member
Thank, that makes total sense. The wires are whatever the stock A body brake switch uses, because I de-pinned the connector and re-crimped the stock wires to it. I was thinking more about the switch contacts wearing out prematurely, but you're right; it will be fine. And at $8 for a new brake switch I'm not going sweat it!
-
