The Ford Barn

whatdoyouwant · 11-24-2022, 10:34 PM

Can someone tell me how many lugs are on the back of the ignition switch and where they go.

pistonbroke · 11-25-2022, 11:23 AM

I'm not certain but pretty sure there are four. The feed or BAT, the accessory ACC, the ignition IGN and the starter STR. So the BAT is incoming power from the battery, the ACC is all your accessory's , heater , radio and such. the coil is the only thing on the ING lug and the starter solenoid is all that should be on the STR lug if it has one(if you have a starter button you wont have this lug)
Tim

rotorwrench · 11-25-2022, 12:09 PM

This was the first year that Ford started using a dash mounted switch. The previous years only had the ignition involved with the switch on the steering column. Bat, Access, and Coil are likely the only terminals. Start function was independent well into the early 50s. The accessory power was primarily for the instrument panel. Battery is power in and coil is ignition only. Lighting was all still independent of the ignition switch. The radio sets had their own fuse if installed so it could be added to the battery terminal or accessory if there is room on the terminal. Most cars that had radio would be connected to the battery terminal so that the it could be independent from other current draws.

whatdoyouwant · 11-26-2022, 09:30 AM

OK Thanks that helps. Where did the start button get power. Was one side of it fused direct to the battery or from the ignition switch?

Mart · 11-26-2022, 11:00 AM

The start button gets a feed from the start terminal on the solenoid and grounds it to the body to pull in the solenoid.
It's the opposite of what would become the norm in later models.

Bob C · 11-26-2022, 12:12 PM

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Here's the wiring diagram from Vanpelts.

petehoovie · 11-26-2022, 12:44 PM

Quote:

Originally Posted by Bob C

Here's the wiring diagram from Vanpelts.

V8COOPMAN · 11-26-2022, 04:09 PM

Quote:

Originally Posted by petehoovie

It should be understood that SOME (if not ALL) '48 Mercurys had a new, dash-mounted key switch, unlike the older, square, Bakelite switches mounted on the column drop, as depicted in this drawing from Mac VP's library. I have read literature indicating that the '48 Merc ignition switches were the same as '49 Ford. I BELIEVE that the picture BELOW is the rear of a '49 Ford switch with three terminals, same as the '47 and earlier switches had three terminals. It would make reasonable sense that they function the same, electrically. The switch in the drawing shows the power coming in from BATTERY. Then, it shows one of the other two similar-looking connections to feed the ignition resistor. The second of the two similar-looking connections feeds a buss bar connecting gauges.

Looking at the '49 switch ABOVE, it appears that the top connection (it's different appearance easily discernable from the other two) is battery power from the solenoid. The use of a simple volt/ohm meter should differentiate which of the remaining two SIMILAR poles is IGNITION, and which is ACCESSORY for the gauges.

Coop

.

Mtn Wudy · 11-26-2022, 04:43 PM

V8COOPMAN ….
FORDs also right …?
Not just Mercs…..
My Ford has that same switch …

Just making sure……

V8COOPMAN · 11-26-2022, 06:29 PM

Quote:

Originally Posted by Mtn Wudy

V8COOPMAN ….
FORDs also right …?
Not just Mercs…..
My Ford has that same switch …

Just making sure……

Wudy,,,, The '48 Ford appears to be the same as Merc.

Coop

whatdoyouwant · 11-27-2022, 11:10 AM

Hey, thanks you guys. This a big help, especially the picture and diagrams.

11-24-2022, 10:34 PM	#1
whatdoyouwant Senior Member Join Date: Jan 2022 Posts: 147	48 merc ignition Can someone tell me how many lugs are on the back of the ignition switch and where they go.

11-25-2022, 11:23 AM	#2
pistonbroke Senior Member Join Date: Feb 2021 Location: Perry Mo. Posts: 485	Re: 48 merc ignition I'm not certain but pretty sure there are four. The feed or BAT, the accessory ACC, the ignition IGN and the starter STR. So the BAT is incoming power from the battery, the ACC is all your accessory's , heater , radio and such. the coil is the only thing on the ING lug and the starter solenoid is all that should be on the STR lug if it has one(if you have a starter button you wont have this lug) Tim

11-25-2022, 12:09 PM	#3
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,440	Re: 48 merc ignition This was the first year that Ford started using a dash mounted switch. The previous years only had the ignition involved with the switch on the steering column. Bat, Access, and Coil are likely the only terminals. Start function was independent well into the early 50s. The accessory power was primarily for the instrument panel. Battery is power in and coil is ignition only. Lighting was all still independent of the ignition switch. The radio sets had their own fuse if installed so it could be added to the battery terminal or accessory if there is room on the terminal. Most cars that had radio would be connected to the battery terminal so that the it could be independent from other current draws. Last edited by rotorwrench; 11-25-2022 at 12:20 PM.

11-26-2022, 09:30 AM	#4
whatdoyouwant Senior Member Join Date: Jan 2022 Posts: 147	Re: 48 merc ignition OK Thanks that helps. Where did the start button get power. Was one side of it fused direct to the battery or from the ignition switch?

11-26-2022, 11:00 AM	#5
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,755	Re: 48 merc ignition The start button gets a feed from the start terminal on the solenoid and grounds it to the body to pull in the solenoid. It's the opposite of what would become the norm in later models.

11-26-2022, 04:43 PM	#9
Mtn Wudy Senior Member Join Date: Nov 2012 Location: Montrose,CO Posts: 227	Re: 48 merc ignition V8COOPMAN …. FORDs also right …? Not just Mercs….. My Ford has that same switch … Just making sure…… __________________ Whether you think that you can,or that you can't,you are usually right....H.Ford

11-27-2022, 11:10 AM	#11
whatdoyouwant Senior Member Join Date: Jan 2022 Posts: 147	Re: 48 merc ignition Hey, thanks you guys. This a big help, especially the picture and diagrams.