turn signal switch wiring

[Bill Young]

Rob, while I agree about the failure rate, the up side of using the relays is that the higher current loads are kept off the toggle switch. This isn't as big a problem with high current rated switches, but really helpful to those guys using the original Lucas switches.
At least a bad relay is a rather simple unplug and plug swap and easy to carry a spare for. Blown fuses are another matter and usually replacing the fuse only results in blowing another one until the problem is found.

[DiDueColpi]

Times two Bill.
Fred

[danmas]

Rob,

I realize I'm coming late to the party, and I should have commented earlier, but I hope late is better than never. I have one problem with your circuits:

By connecting your hazard flasher the way you did, if you should happen to leave the turn signals on at the same time, the hazard flasher circuit will back feed through the turn signal flasher, powering up all the "keyed" circuits in sync with the flasher. Back in '68 when hazard flashers were first introduced, this was a common problem on American cars. Is this a realistic concern? Consider the following scenario: You're driving along when you notice a strange noise, so you pull over to the side of the road to investigate. Being a good citizen, you use your turn signal to let others know what you are doing. You pull off the road, turn off the key, and the turn signals stop. Then, being the thoughtful person you are, you remember to turn on the hazard flasher, but you forgot to turn off the turn signals because they quit when you turned off the key. Now your gauges, radio, fuel pump, etc are all flicking on and off with the flasher. More than just an inconvenience, it may very well put more load on the hazard and turn signal wiring than it is designed to handle.

You will need to add a DPDT switch to the circuit to isolate the turn signals from the hazards. Maybe the attached will be of help. Note that the hazard switch is shown in the "hazards on" position.

Dan

[DiDueColpi]

True enough Dan, if you're using the old bimetal flasher.
The newer electronic flashers are "open" at rest and won't backfeed.
But...the wiring isn't done yet and the isolating switch is a very good idea.

Cheers
Fred

[rficalora]

Good catch Dan!

I noticed I didn't include the turn or high beam indicators on the diagram.  Turn indicators are easy.  High beam seems like it needs to pick up ground coming off the dimmer & flash to pass.  Ok to pick up power off the same headlight power feeding the Park Relay 30 & 85?

And, where's a good source for quality un-insulated terminals?

[DiDueColpi]

Sorry about the indicators Rob, I just assumed that they would be wired in.
Wiring the high beam indicator the way you described will work just fine.
Up here I get my wiring supplies from an industrial electrical wholesaler.
The local auto suppliers only seem to carry that nifty chinese stuff.
Someone closer to your area can probably give you a good ref.
Cheers
Fred

[BlownMGB-V8]

You can get decent crimp terminals such as ring lugs from Digi-Key. You can get them in a strip rolled on a spool which is pretty handy.

JB

[rficalora]

Let's branch this discussion into more general wiring topics -- I started the thread so I guess it's ok for me to hijack it, right?

First, I'd like to have just a few connectors between my dash & the rest of the harness -- to make it easy to remove the dash.  With the above changes for the lighting I think I counted about 18-20 wires.  What sort of plugs would you use & where can you get them?

Same for connection to my keyles ignition -- 5 wires but all 5 are very heavy -- seem like about 12GA so need a connector or two that'll work with that size/current capacity.  I want to make it removable in case it has a problem -- maybe that's overkill?

Next, grounds.  They seem to be one of the bigger causes of electrical problems so I'd put a ground bus up under the dash & ran ground wires for most things back to that bus.  Good idea/bad idea?  

If it's a good idea, does it make sense to use 3 12GA runs (one with wires through the firewal, one to the tail section, & one for the cabin) & splice off of that using the gauge of the power lead for each device?  Or, should seperate ground wires be used for each circuit?

[jim]

Not a valid attachment ID.

I pulled junction strips from mid 90's GM trucks I pick power and ground from the battery all my system grounds
run to the ground strip same as picking up power and I pulled double side plugs from vehiches from junkyard
for my dash I can unplug it and remove it complety all my splices and computer conections are soldered the rest are crimped

jim

[DiDueColpi]

Hey Rob,

Here's a picture of a dash I did for an old truck. The big connectors are weatherpac, the smaller one is a 9 pin computer connector and the battery in and ign out are spade connectors. The ground wire is an eye connector that goes to the chassis. The dash is removeable in minutes and includes 7 guages, ign switch, heater and wiper switches and sound system connections.

Pretty much any connector that will handle the load is fair game. Just make sure that you choose ones that you can't miss connect.

Cheers
Fred

[rficalora]

Susan, let's start with what kind of car, year, etc.

[BlownMGB-V8]

Well obviously it's the Lucas electrics isn't it? ;-)
No, seriously Susan, one of the first things to do is check for good contact at the fuses. Often a little fine sandpaper will clear the trouble right up. If it isn't that it's probably corrosion someplace else.

JB