More wiring questions

[TC Cobra]

Hi Don!

Still sorting out the wiring...

1. The small red wire from the MSD 6AL box goes to #128. I have run both the small red wire and the white wire through the firewall (white wire will be to a "secret" kill switch).

Is there a suitable substitute for #128 on the interior side of the firewall?

2. I have also mounted the fan relay on the interior side of the firewall.
Is there a suitable substitute for #151 for power to the relay?

3. On the fuse block it looks like there are two sockets for flashers. Are they both used? Standard 536 flashers?

4. Any idea where a guy can get the male plug for the backup light switch receptacle on a T-5 tranny?

That's all for now! Gettin' close!

Thanks!
Dwain

[dscott]

Dwain, There aren't any substitute wires for #128 or 151 under the dash. I usually extend them through. The fuse block has 2 flashers, 1 for 4 way flasher and the other for turn signals. The connector can't be found unless you can get one off a junk car. I just cut the wires and splice in a new connector.
Don

[TC Cobra]

Thanks for the quick reply!

[TC Cobra]

Hey Don!

I have some “final” ;-) wiring questions:

1. One of the small bundles coming out of the fuse block has a connector with six male spade terminals - #’s 152, 127, 130, 146, 114 & 156. It also has two separate leads for #’s 146 & 156. There is not a corresponding connector to plug this into. What should I do with it? (I’m not using one of the components anyway eg. A/C, others I am using) Also, the manual says the separate lead for #156 goes to the emergency brake switch. Where is the e-brake switch?

2. The red warning light (brake) on the dash has #130 connected to one of its terminals. What connects to the other terminal to complete the circuit at the proper time?

3. Do the sockets for the turn signals and the four-way flashers use the same type of flasher unit? (536?)

That’s all for now!

Thanks for your help!
Dwain

[dscott]

Dwain, that wire bundle was used for the old style heater so it's not used anymore. You need both flashers, 1 is for emergency flashers and the other is turn signals. Ask for both types at the parts store. The old style proportioning valve used #156 as a brake warning light which is what connected to the red light on the dash. You could use the red light for the fan if you wanted to, just to let you know when it's on.
Don

[TC Cobra]

Good idea for the red light!

What fan wire would go to the terminal?
Would #130 stay where it is?

I have a fan override switch that grounds the sensor. Would that be connected to the light in any way?

Thanks, again!
(almost done!)

[dscott]

You could leave wire # 130 on the light and provide the ground to the light when the switch is turned on. You can just "T" off the switch with the ground.
Don

[TC Cobra]

Cool!

So, just so I understand this, the light will be on whenever the fan is on - regardless of whether I use the override switch?

And, excuse another ignorant question, there's no problem sending voltage to the relay via the sensor wire?

Thanks!
Dwain

[dscott]

Dwain, yes, the light would be on whenever the fan runs. You would be providing a ground through the switch or the sender. I don't understand the second question, which sensor wire?
Don

[TC Cobra]

Sorry, me no explain so pretty good ;-)

The lead to the temp sensor is the one that is grounded through the override switch. (also goes to the relay to trigger the fan automatically).

Since the the relay is activated when the sensor causes the lead to it to be grounded, I am wondering if having 12 volts applied to it (through the dash light) will have any ill effect.

(Hope I've done this correctly)

Thanks!

[dscott]

Dwain, you really aren't feeding 12 volts to the sender. You are supplying a ground circuit. The bulb takes the 12 volts and acts as a resistor and uses up the voltage and turns it into heat (light).
Don

[TC Cobra]

Got it, thanks!

Should hear some noise this weekend!

[TC Cobra]

Well, the good news is the wiring is "finished". The bad news is it's not right >:-/

1. #151 (power to the fan relay) is not energized when the ignition is on. There are two other unused switched sources: #127 & 130. Any reason I can't use either of those to power the fan relay?

2. In a thread above you mentioned teeing off the fan temp sender wire to the override switch and connecting to the other side of the red dash light. When I do that, the fan is always on. Checking the other wire I found it is grounded. That can't be normal (?). If I disconnect the wire to the light everything works OK.

3. None of the guages (voltmeter) work. #130 seems to be grounded.

4. I do have dash lights and the headlight and tail light sockets have voltage.

Any thoughts?

Thanks!

[dscott]

Dwain, it sounds like you have a ground problem. Run a separate ground from the cowl bar to any of the grounds on the dash harness. That should take care of most of the problems. Wire 151 should have ignition power, I would check the fuses, make sure you have one in the fan slot. Let me know what happens.
Don

[TC Cobra]

Don,

I've read all the discussions here about bad grounds causing problems so I've probably "over-spec'd" my grounds. I have a 12 ga wire with several connectors, connected to the cowl bar, that I've attached all the ground wires directly to.

All the fuses are good.

It's wierd that #'s 127 & 130 on the "left over" connector seem grounded when the key is off but test 12 volts when the key is on.

I don't know what to say about #151. I ran a wire from a good connection through the firewall and... nothing. I didn't test it before - I wasn't that far along. Is there something special about 151 that 127 can't substitute?

What now boss?

[dscott]

Dwain, it doesn't matter as long as it's a power wire that comes on with ignition. #130 is the power to all the gauges, you may want to trace that back and see if you have a bad connection where it plugs into the fuse block.
Don

[TC Cobra]

Thanks, Don!

I'll try that.

If a switched hot circuit (white) sees ground when the power is off, (and this is all brand new wiring) what does that suggest?

Dwain

[dscott]

Dwain, I've never checked a hot wire after the power is off. If it reads 12 volts with power on then it must be ok otherwise you would have a dead short. The wiring is probably not really grounded.
Don

[TC Cobra]

That's what I would think as well. My ohmmeter shows zero restance to ground when power is off.

I remember in the "old days" that a bad ground would show up in some pretty wierd ways. The problem is to find the damned thing!!

[TC Cobra]

We have ignition!
We have lift-off!!
The sweetest sound in the universe!

Amazing what a good wiring harness will do.

Roller's done. Body's next!