Siren on M-38

dv3468 · Post by **dv3468** » Sat Dec 13, 2008 8:36 pm

Gentlemen: I am thinking of putting a siren on my 1952 M-38. How were the sirens activated, by a button or switch on the dash board? I was thinking of using a floor mounted MB starter button. Any suggestions would be appreciated.

P.S. Merry Christmas to All!!!

Regards Dennis :

Post by **wesk** » Sun Dec 14, 2008 12:30 am

I was wondering why you wanted to install a siren and then I noticed you are in New Jersey!

Just kidding, I'm from Williamstown down between Camden and Atlantic City.

A spring loaded to "Off" momentary on toggle switch or a spring loaded "Off" button. You could also add a relay

It will be a little easier on your ears to mount it on the bumper or the right fender. Put the relay under the dash and mount it to the battery box or the dash support. Run a 14 gage wire from the battery positive post to the relay and from the relay to the siren. Then add a 16 gage wire from the small post on the relay to the dash switch and a 16 gage wire from the dash switch to a ground.

dv3468 · Post by **dv3468** » Sun Dec 14, 2008 1:33 pm

Thanks for getting back to me Wes. Excuse my ignorance, but what kind of relay switch should I use and why. I was planning on putting a fuse on positive line to be safe.

Thanks again, Dennis

Zane · Post by **Zane** » Mon Dec 15, 2008 2:44 pm

the mechanized sirens on our fire trucks are activated with a floor switch very similar to the mb starter switch, the reasoning for this is so you can keep both hands on the steering wheel where they belong instead of fumbling with a dash switch and causing a wreck, your mb floor starter switch will work perfectly (its a spring loaded momentary switch)

BILLR3408 · Post by **BILLR3408** » Mon Dec 15, 2008 5:08 pm

Hi,
I've got a starter botton mounted on the floor to the left of the gas pedal. It works real good, doesn't stand out, and it keeps my hands free. I never accidentally step on it.
I mounted the siren on the right fender in line with the blackout light on the left fender.

Billr3408

keats · Post by **keats** » Mon Dec 15, 2008 5:32 pm

If you don't want to drill extra holes in your jeep for this installation you can get a piece of L-iron and attach it to the tapped hole in the front frame member where the winch would normally go. Then mount the siren onto the top of the L -bracket. Nice and neat and easily removed. Run wire up through frame and engine compartment and go through the firewall main harness grommet to your switch of choice. Check out photo in my gallery under Gary Keating.

dv3468 · Post by **dv3468** » Mon Dec 15, 2008 8:13 pm

Thanks for the advise guys. I agree with using the MB starter switch on the floor. Wes mentioned using a relay. Does the relay function as a junction box for the wiring? What does it do? Thanks again for the advise.

Regards Dennis

Cacti_Ken · Post by **Cacti_Ken** » Mon Dec 15, 2008 9:37 pm

Relays are used in circuits when a switch can't handle the current needed to operate the electrical device. The relay contact has to be rated to handle the current as well. If a light duty switch is use where high current is produced, then the switch will burn up. Or maybe the wiring will get hot and cause a fire. Proper size wire has to be considered for the device/motor that is to be operated also.
The relay coil is wired to a light duty switch. When the relay coil is energized it causes the relay contacts to close mechanically by electro motive force. the closing of the relay contacts is just another switch rated to pass the current to energize the motor.

dv3468 · Post by **dv3468** » Tue Dec 16, 2008 8:04 am

Thnaks Ken for the thorough explaination.

I am thinking of using a floor mounted, MB starter switch to activate the 12 volt siren, along with 14 gauge wiring. Do you think the starter switch is heavy duty enough to handle the current? I also was thinking of getting the power right from the starter positive terminal. It's the same as going to the positive on the battery isn't it? If the starter switch is heavy enough to handle the current, do I still need a relay? Also what about placing an in-line fuse?
Thanks Again, Dennis

Post by **wesk** » Tue Dec 16, 2008 10:16 am

Generally wiring and switches rated for 6 volt systems can usually stand the pressure applied by a 12 volt system.

Relays are necessary when operating amperage exceeds the rating of the switch or the wires at the switch.

To select a proper gauge wire you need to know the amperage rating of the siren. For example the Timberwolf siren PN 45 is 12 volts 28 amps (with a start up amp draw of 78 amps) requires 8 gauge wire.

Here's a quick comparison of three sirens:

INDUSTRY COMPARISONS

B&M
Super
Chief 60 Amps (start-up 175) Wire gauge 6

Federal
Q2B 125 Amps (start-up 350) Wire gauge 2

TimberWolf
45 28 Amps (start-up 78) Wire gauge 8

dv3468 · Post by **dv3468** » Tue Dec 16, 2008 4:56 pm

Gentlemen:
Thank you all for the great responses to my siren questions. So you know, my M-38 (Serial number 53472) has a 12 volt system in it. Sometime in it's lifetime the engine and transmission were replaced. It now has an early 2A engine and a 1946 dated T-90 transmission. I plan on installing a Federal, Model EG, 12 volt siren on the right fender and use an MB floor mounted starter switch to activate it. What size wire do you think I should use?

Thanks again, Dennis

Post by **wesk** » Wed Dec 17, 2008 5:43 am

We still need to know the amp rating of your siren to offer any suggestion on wire size.

If you can't find the amp rating on the data plate try giving these folks a call: http://www.fedsig.com/tech_support/service_dept/

dv3468 · Post by **dv3468** » Wed Dec 17, 2008 4:09 pm

Wes: Is there anything you don't know about jeeps?????

I just got the siren today, but it's my Christmas Present and "The Boss" wants to give it to me for Christmas! Now I feel like a little Ralphie wishing for his Daisy Red Rider BB gun!!!

I will try the Federal website you sent me in the meantime and let you know how I make out.

Ho..HO..Ho to All.

Regards Dennis

Post by **wesk** » Wed Dec 17, 2008 9:10 pm

Ok, Federal sent me the pecs on the EG and it's 11 amps at 12 volts. So what you have will work. I would use a 15 amp fuse or circuit breaker with it.

dv3468 · Post by **dv3468** » Wed Dec 17, 2008 10:06 pm

Thanks Wes. I would think I could use the same gauge wire that is coming out of the siren. I would think #10 multi-strand wire?