Electrical: Universal Electrical Relays

[jrlemke]

I am using two universal relays to operate my electric cooling fans. I tried the Volvo set-up that was recommended in an earlier post. It will only run one fan or the other, not both at once. I have some universal relays that will work if I can figure out the wiring. The connections are numbered 30,85,86,87, and 87A. I had a diagram at one time telling me where to connect each contact, but it got mislaid and I can't remember where I found it originally. I think 30 is the 12v input, but what are the rest? Help!!- Jim

[Timj]

This should help. I hooked it up to power the headlights. I used it so I could use higher amperage halogen bulbs as well as allowing them to turn off when the ignition switch is turned off.

[jrlemke]

Hi Tim- I've got that diagram, what are the numbers go to?

[PlainBrownR2]

Those are also going to probably be your run of the mill Bosch relays. On a brighter note(or not) I'm guessing that it's just a simple relay setup, and shouldn't be as complicated as what I had to wire on the '55. This was the wiring diagram for the ECU and engine inputs and outputs for that part of the car:



You might be able to use this to some degree, but look at the wiring diagram in the upper right portion for the main relay(relay on the left). They use the same relays as well. 85 is wired from the battery through a switch and 86 goes through the ground for the electromagnet. When the switch is keyed on, that closes the switch in the relay. 87 also comes from the battery, which is also tied to 85, and 30 goes to whatever circuit you want to power.

In my case, when the key was turned on, the main relay closed, which then turned on the ECU, and powered the electromagnetic AND the switch in the fuel pump relay to run the fuel pump. The second relay is also tied to the ECU, so the ECU can tell it when to open and close the relay when the engine is running. The design was also purposefully done for the ECU so when the main relay was shut off, the fuel pump relay shut off, and there was no residual fuel in the lines that could leak past the injectors.

[Timj]

Jim I hope this helps. Number 85 is ground for the relay coil, 86 is the 12v relay trigger, 30 is the high amp 12v fan supply and 87 is the high amp feed to the fans. Also dont forget to use a 1amp fuse to the coil trigger and a higher amperage fuse for the fans. This fuse should not exceed the amperage capacity of the relay. These relays are common in 20, 30 and 40 amp capacities.
TimJ

[jrlemke]

Thanks all! I think I can figure it out now. -Jim

[Jeff_H]

Late to the party, but this should help...



85 & 86 are the coil terminals. Polarity should not matter.

30 is the common terminal, 87 the normally open and 87a the normally closed.

The wiring will depend if your thermostat switch is case grounded ( 1 terminal ) or not (2 terminals). The 30 terminal should go to the battery through a fuse. 87 will go to to the fan power. Fan ground wire comes back to the chassis or frame. For the coil terminals, 85 or 86 will go to chassis ground. The other one will go to the thermostat switch and another wire from that switch to the battery through a fuse.

[sals54]

Also, do a quick YOUTUBE search for relay wiring. There are many to choose from. I found them to be very helpful and far easier to read than electrical schematics.

[StudegaryB]

A 5 terminal standard Bosch relay is very versatile in how it can be wired. The power side can be normally on and off when actuated or normally off and on when actuated. It can be wired to actuate when power applied to the actuation circuit or to actuate when one terminal is grounded. On a motorcycle system I used 5 of the relays mostly actuated by grounding so only 1 wire went to the actuation switch which minimized the wires.