New to working with 12v relays!

[Mike2007]

I have a diesel car and want to install a relay to move 16amps for short time (20 seconds maybe), to a heater pad inside my engine.
This heater pad is wrapped around a flat-plate heat exchanger to thin down veg oil for fuel.

I wanted to use an old Bosch heater plug relay from the scraper's yard, but these have 5 PINS??
What do these five pins carry in the circuitry. Meaning, there would be a direct live from ignition switch to relay, then relay to plugs.

The relay must have a set time for operation (ie. 2 seconds) then off?
Ok, then what are the other relay pins doing/carrying.

 

[davieboy]

pins are:
+ve supply from battery
+ve feed to glow plugs
ignition controlled +ve
earth
+ve to glow plug warning light

picture would help, or might be able to do something with the Bosch part no.

 

[Spark123]

Is there a diagram on the relay?
The bog standard relays which you can buy for a few £s from any motor factors should be ideal for what you need.

 

[Mike2007]

The Bosch relay I was looking at also had 2 "live" terminal posts (heavy cable).
+ve supply from battery ok
+ve feed to glow plugs ok
ignition controlled +ve does this move the load?
earth ok
+ve to glow plug warning light ok

Would this relay have a pre set timer (glow plugs)for the vehicle it was off.
Be good to know what order the pins run in?

Cheers

 

[Spark123]

It depends on the specific vehicle, some glow plug relays I have seen have a temperature measuring input which is used as part of the control to tell the unit when to energize the glow plugs.
Which vehicle did you remove the glow plug relay from?

 

[Mike2007]

It depends on the specific vehicle, some glow plug relays I have seen have a temperature measuring input which is used as part of the control to tell the unit when to energize the glow plugs.
Which vehicle did you remove the glow plug relay from?

Not sure what car, European, it was in a pile! Is there any way to determine which pin does what function without contacting Bosch parts?
The heating method does not have to be precise, as it may take 3 throws of a switch to get heat gain in the heat exchanger(200w).
Just don't want waxy veg oil in HE in winter at start-up.
Thanks

 

[Spark123]

If there's no wiring diagram on it and no information on the vehicle then your options may be a bit limited.