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.

[rob love]

Last post......seems like I am talking to myself. While I am a bit tired today, some of these numbers I had to think twice about. Is this old age setting in??

[Bob Carriere]

.....when the warranty of the Chinese light bulbs is longer than your recall memory!!!!!

Cheers

[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.

[rob love]

Five it is.....I will amend my post. Thanks Wayne.

Mathematics say though that potentially 6 bulbs at an amp a piece require a 6 amp or higher fuse.

[Les Kovacs]

Thanks Rob & Chris for your answers and input....I found a 28 volt, 4.6 watt Wagner dash bulb from my local NAPA as well....I was told that the dash bulbs are the same as the turn signal bulb....bought 5 for about $1.30/each.....did I get the right bulb?

On start up, the turn signal worked for about 2-3 times-the green light flashed a few times then went out altogether....in your opinion, is it the old wiring which in places looks a bit worn, the flasher unit which is screwed high on the fire wall on the drivers side or is it the lever itself?

When the unit failed, the only thing I did 10 minutes before the failure was replace the two front orange lenses....any chances I broke or touched something wrong?

Thanks again,

les

[rob love]

I think your flasher is tired, or possibly had bad ground, but most likely is tired.

It can be replaced with a 2 prong 24 volt flasher if you have trouble finding a solid state one. The solid state flasher connection has 3 pins. Two of them are power in and flash out while the third is a ground. Install a normal flasher across the power in and flash out wires. Whether you cut your existing wires, or figure a way to tie in to the wiring is up to you.

If the lamp merely stayed on, then it would indicate a short, which is easy to find. There are 4 wires at the harness that have to do with the actual lamps. They are easy to remember....even will be for the right, and odd ofr the left. The key is number 460 and 461.

460 is front right turn
461 is front left turn
460-22 is rear right turn/brake light
461-22 is rear left tuen/brake light.

You would simply remove the connector at the signal arm, then with a multi meter set to ohms, put one wire of your meter to chassis ground and the other to the appropriate pin on the harness. Sorry, but I don't remember the abc numbers on the harness, but you can look those up on any SMP schematic easily enough. You will find the ohms reading (resistance) of each lamp will be somewhat similar. But if there is a short, you will find one wire will have a much much higher resistance or even a completely grounded condition. That will tell you what wire you are chasing.

The most common place for a short was the little wiring clips along the frame. They could eventually rub through the insulation of the harness and cause a short. Merely moving the offending clip a few inches along with a bit of electric tape would fix the problem.

I am sure whatever bulb you bought is fine.

Doubtful that changing a lense is your problem, although a lot fo the wires were pretty chewed up where they pass under the hood. As well, they will have been cut and a blue connector installed when guys would pull the engine. Far easier to do that than try and undo the little screw that held the clamploop that secured the wire. You could almost tell how many times the engine had been out by the number of crimp on connectors on those two wires.

[Les Kovacs]

Thanks Rob-I ordered a signal lever-it should be here tomorrow-if its not the problem...I will order a flasher-I guess I will keep lever as a spare. I will get back to this post if things do not work out.

Regards,

les

[rob love]

My money says the flasher, but what do I know.

[Les Kovacs]

Hi Rob....you are most probably correct. I just replaced the signal lever and the blinkers still do not work. With the power on and the new lever placed in left or right position the green light comes on and stays on (no blinking)until it goes back to off. So, I now have two operable signal levers which suggests that it's either the harness or the flasher unit.....I have a flasher on order which should be here tomorrow-I will keep you posted.

As well, I am still stumped as to the oil consumption of about a liter/700-800kms seeing that there is no smoke anytime, the plugs show no oiling, the antifreeze is crystal clear now for over 800 kms and the oil is not a chocolate shake. The oil dripping may be 3-5 drops per day from the rear main seal & the front crank seal. So, I contacted the retired CFB Petawawa mechanic that rebuilt the jeep. I mentioned the oil consumption and details. He said that: 1. A long stroke engine does inherently consume more oil (he did admit that the oil consumption that I had was somewhat unusual) but that he has seen much worse. 2. On rebuilding, he put in new rings (oil control & compression), all new bearings, oil pump etc).....so he too was stumped as to the oil consumption as the jeep only had 1100 kms on it when I bought it after the rebuild. He did mention the PCV valve but I told him that I had that off & well cleaned. He lastly suggested that I change to a straight 30 weight oil for the summer. I also mentioned the engine temp....he said that he was told to keep engine temps down on all of the M38A1 jeeps he maintained so he pulled the thermostats to keep the fluid circulating and that maintained temps to about 130-140F. He suggested that I pull my new 160F thermostat out if I am seeing temps in the 180 F range.
Any thoughts?

Regards,

les
les

[rob love]

Is your flasher harness fused? You don't want to burn out your new flasher, do you?

I would leave the thermostat alone. Nothing wrong with 180°F. The engine should be at full operating temperature to properly burn it's fuel.

Overheating on Jeeps however is not a good thing. I have seen more than a few blocks cracked in between no2 and no3 cylinders.

[Les Kovacs]

Hi Rob....just got the new flasher unit...I have not installed it yet as I did not want to burn it out....not sure how to fuse it...old one is bolted to the upper driver side firewall....I just thought that I would disconnect the battery, unbolt old flasher and bolt in new one then attach harness at both ends then try it out thinking that it would be grounded to the firewall.

New lever light on but not blinking when put into left or right mode.

les

[rob love]

As I mentioned, it could well be a short or it could be a bad flasher. Quite frankly, I would say the odds are 50/50.

You will want to find wire no 460/461 as that is power in to the harness. On the M151A2, the fuse was installed ion the harness near the controller by cutting the wire and installing an inline fuse of 5 amps in that location. But the M151A2 had the harness integral to the main harness. On the Cdn2 and Cdn3 the harness was an add on, so there will be a source of power near to the end of the harness. Find the little tag 460-461 and unplug it. Now you can splice or if you have the material to install the rubber plugs on each end of the inline fuse, you can do it that way. I can tell you though that in service, it would have been cut and a couple blue crimp on connectors used on each end of the inline fuse.

Now when you install your flasher, if the fuse blows on operation of the controller arm, you will know hopefully on which side of the harness to be looking (left or right). If it doesn't blow and the signals work fine, then it was your flasher unit, but you now have the extra security of that fuse in the circuit.

There is a breaker within the light switch that controls all the lighting circuits, but if I recall correctly it is 20 or 25 amps. A little too much juice for the signal circuit to handle I guess.

[Wayne Hingley]

Les; attached is a photo to support Rob's description above. There is a local connection in the 460/461 wire in that area. I used that connection to splice in the fuse (note section with red wires), as I don't like the idea of cutting wires in my harness.

[Les Kovacs]

Thanks a bunch Wayne & Rob..

I have several questions....looks easy but...where do you get the rubber connections to connect to the male and female plug (when pulled apart) with the fuse in the middle?

Right now, when the lever is activated left or right the light turns on but does not flash....does this indicate the flasher or harness?

While the lever was activated (light on with old flasher unit)I checked all connections and wriggle the harness from top to bottom but the light was still lit.....so....

If I replace the flasher with my new one and activate the lever will the flasher burn out if there is a short?

Regards,

les

[rob love]

Sounds like you are going to find out.

The rubber connectors are available from a variety of sources online....they won't be at the local auto parts store though. Don't get hung up on Wayne's perfectionist ways.....a couple blue connectors will work fine. So will solder and heat shrink for a proper long term and reliable solution.

You can always open up the connection at the 460/461 wire and tape a fuse across it just to test. Then you can put in your new flasher and if the fuze doesn't blow, you know it was the old flasher.

Or you can take a $50 chance and install the new flasher without a fuze and switch away. I know which one I would do.

[Les Kovacs]

Thanks Rob....I will go to Canadian Tire and see if I can find a fuse line & add a male connector to fit into the female (460-461?) and a find a female connector to connect into male (460-461?)....and, at the same time try to source a new harness as mine is a little roached.

Many thanks again Wayne & Rob,

es

[rob love]

You can get bullet connectors that are crimp on and will sorta interface with the military connectors, but you will have to tape the connections. They are likely available at Cdn tire, or places like NAPA etc.

I see where Wayne used the fuze holders for the little plastic fuses. To be correct for the time period of the Jeeps, you will want the inline fuze holders that use the glass fuzes.

[Les Kovacs]

Hi Rob....thanks for the connector pics (nothing better than a pic)...I have done some research and came up with Erik Military Supplies.....they have original Packard Military connectors male & female with the rubber casing....to look OEM....I have gone through the jeep and there were may exposed blinker wires that required a new connector or casing so I ordered a whole bunch which leads me to my next question...

As in Christmas light bulbs of the 50's to 80's, if one bulb was burnt out the whole tree went out and you had to find the bad bulb....question...could the whole blinker system have gone out due to exposed wires leading to their respective lights?

I will have a fuse put into the old harness like in Wayne's picture in a couple of days....then I will see if the flasher or lever is the issue. Right now, with power the lever light stays on.....does this mean that there is a short? If so, any hints on how to trace the bad connection?

Thanks again,

les

[rob love]

Les

You have to back and read my many posts in this thread. I have covered how to trace a short, and have mentioned that right now you may only have a bad flasher, or you may have a bad flasher because of a short. The short would be traced by removing the large connector at the signal controller, and then checking for resistance (ohms reading) between the 4 main wires (460, 461, 460-22 and 461-22) to see what readings you get. If all are similar (which they should be because they are all going through a similar bulb) then they are OK. But if one or more read much much lower resistance ( zero resistance indicating a perfect ground) then you know which wire was the problem. Note your problem may be intermittent....you may have to have someone wiggle the wires to find the problem.

So as to your new question: Yes, you can burn out the flasher with just one single wire shorted to ground. Let's pretend there was a ground in the wire leading to the left rear turn signal. Every time you applied the right signal, you would be subjecting the flasher to up to 25 amps of current. At the same time, everytime you applied the brake, you would be causing the little points inside the controller to 25 amps of current. Neither component will put up with that for very long.

All that said, your problem may still be just a bad flasher. An exposed wire is not necessarily a short to ground...it has to touch ground.

[Les Kovacs]

Thanks again Rob.....got it!

OK...right now I got a new a new harness....I have taken off the old one harness which is roached but I will rebuild it, check for shorts and keep it as a spare.

I now have a new issue....my wife was helping me with working on the jeep...as I was in the house she disconnected the flasher to signal lever harness connectors to the rest of the harness leading I assume to the 4 blinkers.....without recording what numbers went with what numbers or letters on the other harness. It appears that the 6 connectors leading to the blinkers are labelled as A, B, L, K, J and so on.....the harness from the flasher to signal lever have labels like 460, 461 and so on....would you have any source that can show me what connectors/numbers go where?

As well, on the harness to blinkers one wire is missing its connectors and was soldered to an open wire to the other harness.

Help would be appreciated.

les

[rob love]

Go to this thread: http://www.mapleleafup.net/forums/sh...ad.php?t=21154

There will be the wiring diagram for the CDN3. Use that as your guide. By looking at the pin on the plug at the controller, you can then discern which wire they should be. Not sure why your harness has letters on the wires rather than the normal numbers.

[Les Kovacs]

Hi Rob....thanks for the link and diagram....although I do have that diagram from a pic off of google and like that one when zoomed in it becomes too blurry to read.

Yes, the harness (old & new)from the lever to the flasher has numbers eg: (460-22) but the harness which carries the wiring to the four signal lamps have letters...go figure?

Thanks,

les

[rob love]

Those letters are likely the pin numbers at the controller connector. I can see most of them on the diagram, along with their wire numbers, so it should be easy enough to translate them into the wire numbers.

Alternatively, you can contact Dave/302 trooper, who posted those diagrams and ask for the full size to be emailed to you. Again, check that thread.