mep 004a no fault lights working plus more

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KLChurch

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Sorry but I'm not used to some of the slang descriptions. For example on my H1 hummer there is a primary fuel tank and an auxiliary. Not a day tank and auxiliary.
Kris
 

KLChurch

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Checked voltage to the upper pump. easier to get to wire. No voltage with run and battle on. The battle light came on when energized.
Kris
 

Guyfang

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OK. The next step is to see why we have no voltage on the B2 and B3 wires. Those wires run back up to the Special relay box. The SP relay box is the box inside the rear right door, with about a hundred canon plugs on it. You need to see if all the plugs are on straight, and tight. If all the plugs are on tight and straight, then we need to pull that box out. Open it up, and see if the A5 card is there, (its marked on the wall where its mounted). Then we need to see if the three relays are attached to the card. Look at the front and back of the card for burn marks.

To check that the wires from the SP relay box, to the B2 and B3 are good, find P5, (the canon plug is marked on the top of the SP relay box as J5) The cable that fits this plug, is P5. You can use a multimeter to check from P5, pin F and R, to the plugs that go to the B2 and B3 fuel pumps.

The wires come into the SP relay box on J5, pins F and R, and then go to TB102-18, where they join together. You can check this with a multimeter.

From TB102-18, a wire goes to the A5 card card. The A5 is screwed to the wall in the SP relay box. Termial 24 is where the wire goes from TB102-18. You can check that with a meter. Disconnect the wire from terminals 24 and 21. There is a diode in between these terminals. To check a diode with a meter use the diode test circuit, or set the meter for ohms. You should get continuity one direction, reverse the leads, and get nothing in the other.

Lets see what you get. Oh, I have been calling the start switch the S1. Its not. Its S2. The old sets are different.
 

KLChurch

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Montgomery/TX
OK will do. This is going to take me a while so There is a chance I wont be able to report back until tomorrow. Just received the power supply and will be testing the fault indicator to see if the lights turn on.
Will report back on that also.
You have been a lot of help. Its too bad our time differences are so different.
Kris
 

KLChurch

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Montgomery/TX
Gutfang,
Update:

Tested the fault indicator and two lights were burned out. Switched the bulbs to prove it. The low oil pressure and over volt lights were burned out.
Need to know were I can get replacements. Anyway I will be reinstalling the unit. Now the low oil pressure light will be working. Also when I put the switch in the run position the low oil pressure light should turn on.
Will be doing the tasks you instructed me to do.
Back to the manuals LOL
Thanks for your help. I'm learning a lot.
Report back when I get the results
Kris
 

KLChurch

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Installed the fault indicator module and toggled the run switch and the low oil pressure light did not come on. This is not good.
Tomorrow I will be working on the Special relay box.
Kris
 

Guyfang

Well-known member
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Location
Burgkunstadt, Germany
Morning!

The light bulbs are found in TM9-6115-464-24P, PDF reader page number 32-33. Figure 7, item 9. NSN 6240-00-155-7836, part number MS25237-327.

There are about 25 other NSN's and Part numbers, if you look hard enough. But no need. I plugged in the NSN in the big sale site. The prices are eye openers. Then I plugged in the part number, and found 10 bulbs for 3.00 bucks. If you want the list of canceled NSN's and Part numbers I can provide it. Great stuff for a long winter night. The list of suppliers is also as long as a Texas road. Almost all, were large company's, that simply bought from OSRAM.

I am fairly sure that the wire from the low oil pressure goes from the sender to the SP Relay box. If there is a problem in the SP relay box, it could and can affect other things.
 
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KLChurch

New member
475
2
0
Location
Montgomery/TX
Morning!

The light bulbs are found in TM9-6115-464-24P, PDF reader page number 32-33. Figure 7, item 9. NSN 6240-00-155-7836, part number MS25237-327.

There are about 25 other NSN's and Part numbers, if you look hard enough. But no need. I plugged in the NSN in the big sale site. The prices are eye openers. Then I plugged in the part number, and found 10 bulbs for 3.00 bucks. If you want the list of canceled NSN's and Part numbers I can provide it. Great stuff for a long winter night. The list of suppliers is also as long as a Texas road. Almost all, were large company's, that simply bought from OSRAM.

I am fairly sure that the wire from the low oil pressure goes from the sender to the SP Relay box. If there is a problem in the SP relay box, it could and can affect other things.
OK. The next step is to see why we have no voltage on the B2 and B3 wires. Those wires run back up to the Special relay box. The SP relay box is the box inside the rear right door, with about a hundred canon plugs on it. You need to see if all the plugs are on straight, and tight. If all the plugs are on tight and straight, then we need to pull that box out. Open it up, and see if the A5 card is there, (its marked on the wall where its mounted). Then we need to see if the three relays are attached to the card. Look at the front and back of the card for burn marks.
Everything looks ok

To check that the wires from the SP relay box, to the B2 and B3 are good, find P5, (the canon plug is marked on the top of the SP relay box as J5) The cable that fits this plug, is P5. You can use a multimeter to check from P5, pin F and R, to the plugs that go to the B2 and B3 fuel pumps.
Have’nt done this yet need a plug diagram for the pin outs. The reseptical is not legable.

The wires come into the SP relay box on J5, pins F and R, and then go to TB102-18, where they join together. You can check this with a multimeter.
Done this but have’nt determined if the continuity is F and R. The plug is not readable. But two pins had continuity.

From TB102-18, a wire goes to the A5 card card. The A5 is screwed to the wall in the SP relay box. Termial 24 is where the wire goes from TB102-18. You can check that with a meter. Disconnect the wire from terminals 24 and 21. There is a diode in between these terminals. To check a diode with a meter use the diode test circuit, or set the meter for ohms. You should get continuity one direction, reverse the leads, and get nothing in the other.
Did this and everything checks out.

Lets see what you get. Oh, I have been calling the start switch the S1. Its not. Its S2. The old sets are different.
Inside the special relay box looks untouched. In fact the insides looks brand new. I don’t think anything is wrong with it.
Why does the lights on the fault indicator not light up? The panel lights work. The battle light works.
After I find the connector pin outs I will be able to troubleshoot the wires to the pumps.
Thanks for the help
Kris
 

KLChurch

New member
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Location
Montgomery/TX
Gutfang
Checked the J5 pins f and r. It seems that there is capital letters and smaller case letters.
Example: F and f , R and r
I got continuity what I believe is f and r pins to the TB102 Board, Number 18 slot. Even with a magnifying glass I could not read the letters. But I got continuity with two pins.
Next I will check the wires going to the pumps.
Everything else you suggested is fine.
So I guess also I will reinstall the Special Relay Box
Kris
 

KLChurch

New member
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Location
Montgomery/TX
Gutfang,
The fault bulbs I have are the screw in type for the fault indicator. (Threaded)
The part numbers I believe you gave me look different. Not threaded
Kris
 

Guyfang

Well-known member
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780
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Location
Burgkunstadt, Germany
Look at he front and back of the A5 card in the SP relay box. See if its burnt.
Look at J5/P5. Have seen a number of times, Pin A pushed back, on J5 or P5.
You don't need to put the bottom of the SP relay box back on, until you get it fixed. Makes it easier to turn the chassis over and make a check.

I was going to tell you to unhook the two wires to TB102-18, and then hook up J5 to P5. Then unhook the two wires to B2 and Br. Ohm the two wires that go to B2 and B3. Since you have unhooked them, you should get an open. Then hook the two wires back together, or have someone hold them together. Then ohm again at B2 and B3 wires. You should get continuity, if the wires are good from the fuel pumps to the TB102-18. I was just a bit slow. didn't get home as early as I planned.
 

Guyfang

Well-known member
7,072
780
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Location
Burgkunstadt, Germany
try resetting the S9 (over speed switch) switch.

Look in the control cube. Is the A4 card burnt, front or back?
Does the A4 card look like its been changed? Loose wires?
Take the two relays out, and exchange them. Try and start.
 

KLChurch

New member
475
2
0
Location
Montgomery/TX
Look at he front and back of the A5 card in the SP relay box. See if its burnt.
Look at J5/P5. Have seen a number of times, Pin A pushed back, on J5 or P5.

A5 card is good and no pins are pushed back I'm reporting one at a time because SS times me out
Kris
 

KLChurch

New member
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Location
Montgomery/TX
I was going to tell you to unhook the two wires to TB102-18, and then hook up J5 to P5

There are 4 wires at TB102-18 two on each side. witch two wires?

Kris





 

Guyfang

Well-known member
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780
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Location
Burgkunstadt, Germany
There are 4 wires at TB102-18 two on each side. witch two wires?


The wires should be, P51D18 and P51B18. They then go to Terminal 24 on the A5 card, on wire number P51E18. The last wire goes to J7, on wire number P51A18.

Also, when using wire numbers, you do not need to use the last two digits. They are the wire size. So when I next write a wire number, like P51A18, I will write it so, P51A. Makes it simpler and quicker.
 
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