Relays Anyone?

[Redskinsjbs]

So I am to the point where I have to definitively decide what gets a relay and what doesn't in my re-wiring of my GT. I am using a push button for the ignition, so there is no need for a relay there.

I have 8 available positions which are tentatively organized like so...

Block 1

1 - Headlamps Low
2 - Headlamps High
3 - Electric Fuel Pump
4 - Horn???

Block 2

1 - Fuse Panel #1
2 - Fuse Panel #2
3 - Radiator Fan
4 - Heated Glass???

What I want to know is should I wire a relay for the horns and heated glass or is there another circuit that would benefit more from a relay?

[First opel 1981]

The horn relay is a good idea and the one for the glass with an on/off switch won't hurt. Both would take the strain off of the switches which is what your intent is, correct?

Are you using standard relays or solid state? I have found that solid state relays are wonderful.

[blancojp]

Originally Posted by Redskinsjbs So I am to the point where I have to definitively decide what gets a relay and what doesn't in my re-wiring of my GT. I am using a push button for the ignition, so there is no need for a relay there. I have 8 available positions which are tentatively organized like so... Block 1 1 - Headlamps Low 2 - Headlamps High 3 - Electric Fuel Pump 4 - Horn??? Block 2 1 - Fuse Panel #1 2 - Fuse Panel #2 3 - Radiator Fan 4 - Heated Glass??? What I want to know is should I wire a relay for the horns and heated glass or is there another circuit that would benefit more from a relay?

Radiator fan gets a relay when the fan is high on amps. Other than that, I would just have 2 30A relays one for the horn and the other for the glass.

[Redskinsjbs]

Originally Posted by blancojp Radiator fan gets a relay when the fan is high on amps. Other than that, I would just have 2 30A relays one for the horn and the other for the glass.

I have the relay for the radiator fan because I have a temperature control switch that only turns it on when needed

Originally Posted by First opel 1981 The horn relay is a good idea and the one for the glass with an on/off switch won't hurt. Both would take the strain off of the switches which is what your intent is, correct? Are you using standard relays or solid state? I have found that solid state relays are wonderful.

Exactly. The whole idea is to remove as much load from behind the dash and the antique switches as possible. For now I am using standard relays because of their cost. When they fail, I will switch to the solid state ones. I did that for the flasher relays in my (Dad's) Honda and they are SHWEET!

[wrench459]

Originally Posted by Redskinsjbs Block 1 1 - Headlamps Low 2 - Headlamps High 3 - Electric Fuel Pump 4 - Horn??? Block 2 1 - Fuse Panel #1 2 - Fuse Panel #2 3 - Radiator Fan 4 - Heated Glass??? What I want to know is should I wire a relay for the horns and heated glass or is there another circuit that would benefit more from a relay?

I would think about using a main relay to power up block 1 so thats it only hot with the key on.

Move the fuel pump to block 2 thats wired to B+ (oil pressure switch & dual pole relay for the fuel pump)

Move the rear glass heater to block 1

Whats fuse Panel 1 and 2 doing?

[hrcollinsjr]

Originally Posted by wrench459 I would think about using a main relay to power up block 1 so thats it only hot with the key on. Move the fuel pump to block 2 thats wired to B+ (oil pressure switch & dual pole relay for the fuel pump) Move the rear glass heater to block 1 Whats fuse Panel 1 and 2 doing?

I'm not going to question Dan's suggestions as he probably has good reasons for them. I'm not planning on putting that much thought into it. Seriously though he has some good reasons for doing it the way he suggested.

My suggestions as far as what needs relays. Obviously anything with a high amperage draw.

Headlights - Opel did it and you want max. voltage for max. brightness!
Electric fan - commonly done on factory equipped cars.
Fuel pump - again done by factory
Rear window defrost - way the factory does it.
Pwr. windows & locks (if you ever install any) all use relays.

Depending on what you're doing you may want to look into circuit breakers in some instances instead of fuses.

HTH,
Harold

[Redskinsjbs]

Originally Posted by wrench459 I would think about using a main relay to power up block 1 so thats it only hot with the key on. Move the fuel pump to block 2 thats wired to B+ (oil pressure switch & dual pole relay for the fuel pump) Move the rear glass heater to block 1 Whats fuse Panel 1 and 2 doing?

So Fuse panel #1 and 2 relays are what switch the power on to the rest of the circuits in the car when the key is in the 'ON' position. All of the other relays have their trigger circuits as a part of the fuse panel and therefore cannot be triggered unless the key is in the 'ON' position. The only relay which breaks this rule is the one which powers the electric fuel pump. This one is to be wired in accordance with Otto's instructions from this thread: http://www.opelgt.com/forums/66203-post14.html

Now why are you moving the relays to different blocks? Is it just an organization thing? Clue me in...

Thanks and HTH

[hrcollinsjr]

Originally Posted by Redskinsjbs The only relay which breaks this rule is the one which powers the electric fuel pump. This one is to be wired in accordance with Otto's instructions from this thread: http://www.opelgt.com/forums/66203-post14.html

Dan's suggestion on wiring the relay for the fuel pump is his attempt to accomplish the same thing Otto was seeking to do. Otto's stuff is usually well thought out but almost anything can be improved on. When it comes time for me to wire up an electric pump, I'll definitely look at what he's done. I may wind up copying it exactly but I can guarantee I'll try to improve upon it first.

Harold

[Aardvaark]

One relay hasn't been mentioned.
If your not much of a risk taker and have converted your alternator
over to one of the one-wire GM alternators, be aware that the self
excited field regulator used in these is hard to come by out on the road
away from home. The auto parts stores generally don't carry replacement one-wire alternators or the regulators for them in stock so if it fails, you may be stuck for a few days awaiting repair parts. But if you keep a spare self excited regulator with you, about any shop can repair your existing alternator.
The self excited regulators can be purchased from: Transpo Electronics - The world leader in automotive related after market electronics... or elsewhere if you are inclined
to be prepared just in case.
However, the one-wire alternator may be able to be repaireable as a three wire regulators. Not sure.

Many of the GoodGuys rods have one-wire alternators and some people carry an extra regulator just in case.