I'm trying to install some extra lights in my Wrangler. I read that relays are needed. I snagged a decent looking box from a Saab at the local JY. I thought it wouldn't be much trouble to transfer power to my switches and have juice to my accessories. The problem is I can't make the relays work.
I pulled one of the relays and used blade connectors on jumper wires (fused) to try and switch a new dome light just to see how they should be wired. I followed what was on the inter webs but can't seem to make the 3 prong lighted switch do anything.
My relays from the Saab are Bosch 5 prong with diodes between pin 85 and 86. I tried different configurations. Pin 87a always has power and with some configurations, the relay will click when I connect it to the battery using a fuse as a quick connect/disconnect. All the diagrams seem to show installing relays without diodes.
My understanding, without really knowing anything about relays is,
30 pin is the 12 guage fuzed hot wire direct from the battery.
87 goes to the light or accessory I want to use.
87a isn't used.
85 is a ground. Grounded to the frame.
86 is low voltage wire going to the middle prong on the 3 prong switch.
The switch is grounded to the frame.
The power is a low voltage wire, fused, from the battery.
The middle ACC prong is from the relay.
Where am I going wrong?
Are there easier to work relays that don't have the diode and I can just put them in my new Saab box without using the Saab relay configuration (lots of wires, very messy)?
I've always wired my relays
87 To Accessory
After re-reading think you have the switch itself backwards. The Relay should hook up to the bottom of the switch and power to the middle prong. Believe it or not I have had a switch or 2 picky about it......
There SHOULD be something on the switch showing 12V which would be power supply
One of the switch prongs is brass and has supply written above it. The other 2 prongs are silver ACC and ground written above those. I tried swapping the 2, ACC and supply but it blew the fuse. Maybe the switch is bad.
Thanks for the help. I'll try again next weekend. Something will work eventually.
You can go either way with pin 87 and 30, I like to use pin 30 as the output, whatever you put to 87 will switch to 30, if you are powering up lights use pin 86 from whatever you want to switch lights on, pin 85 to ground, pin 87 goes to power with a fused connection of a wire at least 12-14 gauge (depending on amp load), and pin 30 to lights, using right gauge wire is important especially if using tradition style lights (not led). A good tip, don't ever tap into another circuit for ground.go to chassis or similar, And always fuse your power source.
I'm gonna jump back on this next weekend. Please check my math as I want to be sure I'm following your advice.
Fused hot wire from the battery to pin 87.
86 goes to the switch.
85 grounded to the engine or frame.
30 gets fused 12-14 guage wire to the lights.
You don't have to ground it to the engine but a nice clean surface on any solid location will do. Yes on the rest. You should use 12-14 gauge to lights as well from pin 30, I try to use same gauge wire to all points except the one from the switch. That one can be 16-18 on pin 86.
This is along the lines of what I am trying to do. How do I wire up a fuse block with a relay? I want the fuse block to be hot only when ignition is on. So, on the relay I would run:
30 to 12v power (fused)
87 to fuse block
86 to some wire that is only hot with ignition on (Any good suggestions here?)
85 to ground
If I run any lights later on, will this setup allow me to go straight to the fuse block without adding additional relays?
Any help is appreciated
I would recommend going with a solenoid to turn on the fuse block. Amps can add up quick through a Fuse Block and your typical Autozone relay can hold about 40 amps (4 100 watt KC lites will be very close to 40). A Continuous Duty solenoid (Google it)can handle a LOT more power. The ones we use on our buses power an entire Fuse Block and I can get them at any International for $30. Setup is basically the same as a relay. Power in, Power out, Ground, and switched power.
You would, however, still want to use relays after the Fuse Block. If you hook up power normally you'd have to go from Power to Switch to Item. All relays do is eliminate the feed/routing off the switch that usually can't handle the amps anyways (and catch fire when you turn them on lol). And the more wire you use the higher and more expensive gauge you need. So in essence you would go from Power to Relay to Item and using a LOT less Wire and not straining the Switch at all. Not to mention you'll also have a lot less resistance so more Voltage available to the item that needs it.
My setup is Battery to 3rd party fuse block to relay then Item. I have ONE power source for ALL my switches so I only run one wire to my dash and feed all my switches. The Fuse Block supplies the main power to my relays for each item. But I keep mine fed off the Battery so I can turn on my Off Road lights (and whatever else I have hooked up) with the engine off.
Thanks! I didnt read this after work, I just went to the garage to install the parts that I already had. I got it all wired up and I have to say that I am pleased with how tidy it all looks. Even better than how it looks...It Works!
As far as the lights, I intend to go LED when or if I add lights. Any accessories that I run through the fuse block will be much lower draw than the old energy hog lights.
You actually did answer a question that I was curious about. If I decide the LEDs are just not worth the money, do I need to install relays for that switched circuit. I think the answer is YES.