Info needed: M38A1 flasher/signal unit on the steering column

[Les Kovacs]

I have a 67' M38A1 CDN 2....it has the military (D.C. Electronics Inc.) flasher/signal unit on the steering column...the green bulb on the stalk is burnt out....I have taken the clear 28V bulb out but it is so corroded that the number on the base is impossible to read....can anybody tell me what the bulb number is and where I can buy one? Once this bulb burnt out....it left me with no turn signals at all....is this normal?

Thanks,

les

[302Trooper]

Les,

Contact Rob Love or any of the SME's in the post war vehicle group. You should get a quick response there.

[rob love]

1829 or an 1819. Either one will do.

A quick check shows both are available under those trade numbers. The price ranges from a buck to $2 each. The 1829 bulbs are actually on the shelf at my local NAPA.

[chris vickery]

Les, not sure regarding your bulb issue leaving you without dogs, guess replacing with a new one will tell.
On my CDN3, I had signals issues which took some time to figure but the main culprit was the signal switch itself, as they use an integrated circuit board which can burn out which was my case. I had a perplexing issue as I also had a signal wire which was bared in a small spot leaded to sporadic problems as it grounded out against sheet metal. May have possibly lead to the signal switch malfunction previously noted.

[rob love]

Chris

Absolutely that would be what burns out your contacts in the signal switch. Without a short in the equation, those switches will last decades. I can count on one finger how many of those switches I had to replace in the 40 years I have worked on SMP vehicles. The same is not true for the solid state flashers however. They do not like the heat, yet on several vehicles the military mounted then under the hood. The MLVW has it in very close proximity to the exhaust manifold.....poor planning in my mind on an otherwise stellar truck (in it's day). The flashers are also very much adverse to short circuits.

Wire no 460-461 (IIRC) is the power wire from the light switch to the signal controller. A wise man would put a fuse into that line of about 10 amps or less. That was an authorized modification to the M151A2 in Cdn service. At most, you should be illuminating 6 bulbs max of the 1683 trade number. That is only if you put on the 4 way flashers while towing a trailer. Those bulbs draw just over 1 amp a piece, I'm not sure what the flasher unit draws but being solid state my guess is it's negligible. The fuse will protect your signal controller as well as the flasher. Both are somewhat expensive, and both are likely going to be in US dollars when you do order one.

The first indication that you have a short will be that when you turn the signal arm, the indicator light will stay on.

As to your original question about the indicator lamp causing the lights not to work, no,that little lamp has no bearing on the remainder of the system.

[rob love]

By the way, I mentioned the 1683 bulb. They are available from NAPA under 2 different suppliers. If you order them under NAPA brand (LMP 1251) they will run you $5.77 retail or 3.73 trade price. But if you order the Trylight brand (TRL 1251) they will only run you $1.39 retail or $1.10 trade price.

Warranty on both is the same 30 days.

[Wayne Hingley]

Originally Posted by rob love

Wire no 460-461 (IIRC) is the power wire from the light switch to the signal controller. A wise man would put a fuse into that line of about 10 amps or less. That was an authorized modification to the M151A2 in Cdn service. At most, you should be illuminating 6 bulbs max of the 1683 trade number. That is only if you put on the 4 way flashers while towing a trailer. Those bulbs draw just over 1 amp a piece, I'm not sure what the flasher unit draws but being solid state my guess is it's negligible. The fuse will protect your signal controller as well as the flasher. Both are somewhat expensive, and both are likely going to be in US dollars when you do order one.

Im not a "wise man", but I Installed a 5 amp fuse in my system per this same advice several months ago here: http://www.mapleleafup.net/forums/sh...use#post240252 See posts 62, 63 & 71.