adding ON/OFF switch to control glowplug relay - Page 2 - PeachParts Mercedes-Benz Forum

Whiskeydan · #16 01-22-2010, 10:41 PM

Quote:

Originally Posted by TurboSDL

does it say the pin numbers on there? and is pin 31 a ground?

Yes and yes.

If you pull the small connector you should see the relay connector pin numbers on the relay. The connector will come apart and you can remove the harness wire from #31 and repace it with a new wire going into the cabin. In the cabin it connects to one side of a 'normally open' spst switch. The other side of the switch will connect to a nearby ground.
Ideally you should use a momentary pushbutton switch you will have to hold closed and there is no chance of leaving it in the "on" position.

If/When you get a replacement relay it should be easy to put back to the original configuration.

TurboSDL · #17 01-26-2010, 07:28 AM

so basicly im just going to be opening the connection to pin 31 in order to keep it from coming on and closing the connection with a push button would glow the plugs?

could i also cut the wire for pin 31 and solder a wire to it, then bring that solderd wire to the cabin, hook up a switch of some sort, then hook up another piece of wire to the other side of the switch and connect that to the other end of the cut wire which is still plugged into pin 31 on the relay?

basicly just cutting the wire for pin31 and hooking up a switch to that; leaving all the wires plugged into the relay but just splice the switch into 31 that way the relay still will use the ground that pin 31 is hooked up to, but ill be interrupting the ground with a switch.

Stevo · #18 01-26-2010, 02:28 PM

All that sounds like a potential bucket of worms, why dont you just dispense with the relay since it will be in the system to cause possible further trouble. Your installing a switch anyway all you need is a solenoid.

leathermang · #19 01-26-2010, 02:38 PM

Why don't yall really ' go to ground' on simplicity...
and use a Mercury switch... which you can run the full load through...and skip having the solenoid in the circuit. A gravity off ( push lever on )Mercury switch is about as foolproof as it can be made.

TurboSDL · #20 01-26-2010, 03:11 PM

ya kno im thinkn about goin for that solenoid. how much do they cost? and are they behind the counter at the auto parts stores or somwhere on the shelves? if they are behind the counter what do i ask for?

Diesel911 · #21 01-26-2010, 03:24 PM

On mine there is a Purple wire coming from the Glow Plug Relay to a Junction Block.
A White Wire comes up from the Starter Solenoid. That White Wire gives the Purple Wire Voltage when cranking and keeps the Glow Plugs on during cranking.

If you were willing to do with out the having the Glow Plug Relay on during the Starter cranking you could simply disconnect the Purple Wire from the junction block and hook your Switch to that wire and the other to a source of (+) Voltage.

Graplr · #22 01-26-2010, 03:26 PM

Quote:

Originally Posted by TurboSDL

ya kno im thinkn about goin for that solenoid. how much do they cost? and are they behind the counter at the auto parts stores or somwhere on the shelves? if they are behind the counter what do i ask for?

You can use a solenoind or you can just use a high amperage relay. Both will accomplish the same thing.

I realize this is a different vehicle but the concept and the wiring will be the same.
http://www.dieselplace.com/forum/showthread.php?t=340695

He used a Ford Starter Solenoid from Adv@nced Auto. He lists he got it for $12 and includes a part number.

Stevo · #23 01-26-2010, 03:29 PM

I used an old Ford truck solenoid, ask them how to hook it up at the auto parts, pick up your 15 amp push button switch there also. You might check into Greg's Mercury switch idea, save yourself a step maybe.

Diesel911 · #24 01-26-2010, 09:49 PM

I have a similar Fordy type Solenoid that I got for a couple of bucks at the Junk Yard and has been my Volvo since about 1992. It has no Fuse, but has worked perfectly.

However, I think I remember the origional poster saying he did not want to cut up the Wires going to the Glow Plug Connector.
You would have to cut them or replace them with new fabricated wires.

DrewGerhan · #25 01-26-2010, 10:39 PM

AutoZone part F492 or F496.

Stevo · #26 01-27-2010, 11:29 AM

Quote:

Originally Posted by Diesel911

However, I think I remember the origional poster saying he did not want to cut up the Wires going to the Glow Plug Connector.
You would have to cut them or replace them with new fabricated wires.

My "79" has the strip fuse on the firewall but on the "later" cars I wonder if you couldn't bypass the innards of the stock relay, use the wiring harness IN and strip fuse, coming out of the old relay with one wire and to your push button/solenoid. I guess I could peek inside an old relay and see, seems something like that would be the slickest way to do it on the "later' setups.