TACOM SWITCHES and the M35

[saddamsnightmare]

MArch 4th, 2008.

Does anyone have a copy of the installation and operation instructions for the TACOM Blackout light switches that replaced the old three levers on the rebuilt M35's??
I am particularly interested in avoiding the static discharge issues that affect the electronics on installation (if done improperly), and the opoerational aspects, which, I understand, are quite different from the three way lever setup. Any information would be appreciated, and photocopies of the instructions will be assured a good home.
Thanks Again,

Sincerely,

Kyle F. McGrogan

1963 Swiss Mercedes Benz Unimog S404.114
1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Storm and Vietnam veteran Deuce.

 

[FMJ]

I have 2 M109A3's that have the new switches, took some button pushing but I figured out how to operate them. Would be interested as well, as to the proper operation of these switches.

 

[emmado22]

Those switches SUCK... Keep your old switch with you in the truck for when the electronic ones fail... Because they will, then you wont have lights at all. Ask me how I know......

 

[gimpyrobb]

I would think that if you install the switch in the dash before you hook up the plug on the back it *should* be grounded and help eliminate the static.

 

[emmado22]

Thats just part of the problem. The electronics are WAY too sensitive for 24V, and any spike or dip will fry them. I fried mine (and it was grounded back to the BATTERY itself) by turning on the truck when the light were already on... BUUZZTTTT.. and no more lights.... Trust me, or see for yourself eventually (or not see to be miore correct).............

 

[CCATLETT1984]

keep it simple stupid, its a great thing to live by

 

[ARMYMAN30YearsPlus]

I have to say that most of these problems were with the first version of the switch. I have had one on my duece for over three years and it works great. I just like the lit up segments. I do not know if they changed the NSN on these but I am pretty sure I have the newer version. In my time I have seen a good deal of three lever switchs failing too. I think the idea was to Soldier Proof them and an engineering glitch created the problem with the early ones.

 

[justsomeguy]

on 10 of my 1025's that had those switches only one has survived more than a year. You'll need to run a ground strap from the screw ground on the swicth to a good chasis ground. I am not fond of them. They look nice just in my opinion not reliable.

 

[ARMYMAN30YearsPlus]

The HMMWV is where most of the problems occured due to the fiberglass and lack of a ground that would last through all the demands placed on the vehicle. If the units are properly grounded they should not suffer from normal use and TACOM would not have sourced these and approved them without a great deal of testing and evaluation. I am not sure where my old three lever is but as I gain trucks I have more of them around.

 

[cranetruck]

The military specifications or requirements must have changed also, the tactile feedback part is no longer present. Look at a vintage military radio and note the shape of the knobs and controls, designed to be "felt".

As previously discussed, the lock lever on the 3-lever switch may fail in some cases, but the light switch portion still works. Also the wiping action of the switch contacts help keep it clean and operational. After 40-50 years of non-use, the silver plated contacts may no longer have a low resistance.

 

[acetomatoco]

New 3 lever switches $50 ea rampartsllc@aol.com

 

[saddamsnightmare]

MArch 5th, 2008.

Thanks Gentlemen, for the input on the TACOM switch. I E-MAiled Kenny for the installation and operation instructions, if anyone's gonna know about them, he'll be it. I'll ground the switch before I hook up the rear connector, but I think Armyman30's right, the deuce is all metal and the Army ordered about a million or two of these, I'd think by now they got the bugs out, if not, I'll get a very quick course in electronic versus electrical engineering. The 3 lever's not necessarily foolproof, or the civillian manufacturers would have taken to it also, and I'm sure there's room in the truck for the old 3 lever to be stashed somewhere against need.
I'll also point out to you gentlemen who are conservatives- there's a lot of Fort Model "T"'s running around today with a 12V alternator and electronic ingnitions in place of the generators and tremblor coil units, so things can change for the better.

Regards,
Kyle F. McGrogan
1963 Swiss Army Mercedes Benz Unimog S404.114
1971 KAiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Storm and Vietnam Veteran Deuce.

 

[emmado22]

I wish you the best of luck with the switch, but there is a reason all the HMMWV rebuilds get the OLD style switch put in when they get rebuilt..

Bottom line, the contractor made a crappy product, and Uncle Sam bought it... And when it fries, Uncle Sam buys more. Contractor points to "improper grounding" and is off scott free... It's a evil cycle, with your tax dollars paying for a poorly desgined switch...

 

[cranetruck]

.......I'll also point out to you gentlemen who are conservatives- there's a lot of Fort Model "T"'s running around today with a 12V alternator and electronic ingnitions in place of the generators and tremblor coil units, so things can change for the better.....

Guess I'm one of the "conservatists", my belief is that some things can't be made better, just differently....

 

[cranetruck]

....The electronics are WAY too sensitive for 24V, and any spike or dip will fry them. I fried mine (and it was grounded back to the BATTERY itself) by turning on the truck when the light were already on... BUUZZTTTT.. and no more lights ......

The simple solution to this is to add a toggle switch in the feed line (wire #10 to "F" terminal) and making sure it is OFF when the engine is cranked or shut down, just like we are supposed to do with the radios/intercoms etc.
Running the starter can produce some horrendous voltage spikes, in particular when the there is a poor battery connection....see my past posts on "load dumps".

 

[saddamsnightmare]

March 5th, 2008.

Is the present three lever switch routed from the battery through a terminal or fuse block direct (I don't have any of my manuals handy at present), or is it fed through the master "Off-ON' switch up by the engine kill handle?? I note that the master "OFF-ON" takes out all the guages and such, but obviously doesn't diable the starter motor. I guess one could get into the main feed wire for the three way, cut and route to an auxillery switch like in the radio switch drawing above, then back to the TACOM switch. Would it be possible to substitute a capacitor in the circuit to absorb the initial inrush of current??

Sincerely,

Kyle F. McGrogan

1963 Swiss Army Mercedes Benz Pritsche Unimog S404.114
1971 Kaiser Jeep M35A2 Wo/W "Saddam's Nightmare" Desert Storm and Vietnam Veteran Truck

 

[cranetruck]

The 3-lever switch is connected directly to battery and can be used without the in-tank pump running, for example.
A capacitor may or may not do it, a very large zener diode or a varistor large enough to absorb a load dump could do it. Look at the MX-7777 guts (designed to handle all eventualities at up to 50 amps I believe) and you'll know that an ON/OFF switch is the way to go....

 

[Boosted_Nelson_Inc.]

Just Google TACOM switches. I found 2 pages of instructions from the supplier.

 

[cranetruck]

Thing is, that there is probably still power applied even when "off". A circuit diagram would be needed to say for sure, but that's my guess, otherwise, the touch pad couldn't be activated after it's turned off. Adding an external switch that can handle the max current rating of the light switch would be an easy way to protect it.

 

[whatadeuce]

My Truck #3 has issues, and After reading this thread, I am going to install a three way switch...Thank you all...