My resistor can't be bad!?

I have two all stock m1009s. No bypasses or anything. Num 1 I put diesel rx 70s in immediately as originals were not working g and swelled. No problem for two years now. Num 2 m1009 I decided to do the same. It appears all original right down to the u joints and handwritten codes in white and yellow marker on various undercarriage locations. Was starting great but 2 plugs ohmed out bad so I put diesel rx 70s in it as well 2 were swelled no biggie. Couldn't read but 2 of the plugs nomenclature...one 070 and one 13g...rest were unreadable. 3 were swelled so plugs were mixex bUT fIred up good still. After the swap out I turned the ignition to the run positionand noticed the seat belt buzzer came on as usual while waiting on the wait light but only for a sec then quit. After wait light it fired right up so I went underhood to measure relay output on orange wires at bottom of relay for 10 to 15 volts. I used the ground stud of drivers alternator for black lead then noticed the resistor smoking and green glowplug wire near driver side firewall melting and one other starting to. So I shut her down. All plugs were blown by ohm test. 1.5 to 1.2 is what book calls for the range. 5 were swelled. Remember reading about a bad batch of diesel rx on the market so I threw another set in after replacing glow plug wire with correct fusible link wire. Soldered it in to the wedding band connector in the loom. All others appeared good and had continuity with the audible setting on meter but I didn't ohm them. Truck started fine...no hot spots on wiring anywhere...no smoking resistor...thought all was good. It got down to 40 degrees and noticed it dint fire up instantly as usual so I ohmedthe plugs and only 2 were bad and swelled. Did the checks in the dash 20 and it says my resistor is bad. Measured it disconnected through each end of the wires without my fingers on them...4 then 3 then 2 then 0 ohms after about 5 secs leading me to believe failed resistors. But my other truck (number 1) the ohms check does the exact same thing! 4 3 2 1 0 ohms after about 5 secs. And I have a parts truck and it's resistors do the same! So I don't think the resistor bank is the problem. Ive been reading so much here on steel soldiers and have confused myself! Card looks good too...no burning at least and all diodes in place. I do have a brand new sealed in package oem card...7842 I believe but am hesitant. Also have a set of bosch deratherms on the way. I'm definately gonna have the multimeter on the glowplug relay output terminal and propped up against the windshield for round three looking for that voltage drop. Yes I had 24 volts in to top of relay b4 just forgot to mention it. The most curious thing I read on here was something about the seat belt buzzer being tied in....along with some other items. I didn't notice if my water in fuel light was on....that was one of them. I used my audible function to verify all fuses were good...they were. But that seat belt buzzer hasn't worked since round 1 and I think it's a clue. I could swap stuff since it appears to be original but am scratch g my head! (The relay is not original). I'm not good with schematics but I got one. Any input would be appreciated. Want to keep it pure if possible. Thx for the long read

Also forgot...relay is hooked up correctly...red on top from resistor....two orange and the sensing wire on the bottom relay. Pulled card also and no burns. It is original style. Wiring is not hacked...relay did the cycling in wait mode....and did the after glow. Thx

Not familiar with rx70.glow plugs. I have a completely 100% stock system and use A C Delco 13 G glow plugs have for over 20 years. GM 5613939 will get you 8 original GM glow plugs at a dealer for about a $100.

PLEASE use paragraphs.
It’s like reading a brick.

Most guys use AC60Gs here
Others use the AC13Gs.
Few use Bosch.
Either works.
I wouldn’t bother with speciality/off brands. Too many unknowns.
Stay away from Wellmans.

Check all your connections all the way down to the GP tab.
Each and every GP wire to make sure all the links are good.

Ordered a set of Wellman on line, they showed up marked Diesel RX. RX70 on each plug. Called the vendor and he assured me that these are the same glow plug and they will not be marked Wellman. I did a little research and he was correct. Maybe a buy out or something. I did let him know it's misleading to use glow plugs marked Wellman in all sales photos....for whatever that's worth. Since I am trying to keep my 1009 as true to original as possible I am using them....hopefully not a bad decision to deal with later. Good luck and hope this maybe cleared up the RX70 question.

cucvrus said:

Not familiar with rx70.glow plugs. I have a completely 100% stock system and use A C Delco 13 G glow plugs have for over 20 years. GM 5613939 will get you 8 original GM glow plugs at a dealer for about a $100.

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Sir...does that AC Delco 13G have the correct spade connector for my factory glow plug harness? I understand some need modified to work. Just curious. Thanks

YES. 13 G A C Delco is a 3/16" spade the same that came from the factory. Been using 13G for over 20 years. Still going. All stock and not a problem. Last week I solved the biggest problem I ever had with a CUCV. No problem.

Tinstar said:

PLEASE use paragraphs.

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Yep.

You'll never know how many people who might have been able to help you just passed on by when they saw that mess. Some will, some won't. If you can't put in the effort to make your message readable, there's sure no reason anybody should put in any effort to help you.

By the way, I did read your title. Yes, resistors can be bad.

If you have a truck that hasn't been bypassed at resistors bank or a removed one could you check your ohms for me? Tm says 28 ohms and if not replace it. Tm also says to remove from firewall to check but it doesn't appear to make a difference since the resistors aren't grounded to the case or body. I just took the wire loose from the buss bar and the top of the relay to check. Thanks and no rush as my mom passed away and will not be able to work on truck for a few days. My good truck and my bad truck both read the same...4 then 3 then 2 then 0 ohms after about 6 seconds . There are all these mistakes in the tms and am just curious as to what others are reading and if yours is holding at 28 ohms. Been looking thru the shcmatics and that seat belt buzzer water in fuel light circuit is tied in with alot of stuff also.
Somewhere in the forum I saw a post regarding the card and a malfunction all tied in with the above mentioned cicuits is what's got me stuck on this as that's what mine did after my original glowplug swap. The seat belt buzzer activated for a short second and hasn't worked since. Thx

bryfor said:

If you have a truck that hasn't been bypassed at resistors bank or a removed one could you check your ohms for me? Tm says 28 ohms and if not replace it. Tm also says to remove from firewall to check but it doesn't appear to make a difference since the resistors aren't grounded to the case or body. I just took the wire loose from the buss bar and the top of the relay to check. Thanks and no rush as my mom passed away and will not be able to work on truck for a few days. My good truck and my bad truck both read the same...4 then 3 then 2 then 0 ohms after about 6 seconds . There are all these mistakes in the tms and am just curious as to what others are reading and if yours is holding at 28 ohms. Been looking thru the shcmatics and that seat belt buzzer water in fuel light circuit is tied in with alot of stuff also.
Somewhere in the forum I saw a post regarding the card and a malfunction all tied in with the above mentioned cicuits is what's got me stuck on this as that's what mine did after my original glowplug swap. The seat belt buzzer activated for a short second and hasn't worked since. Thx

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A smaller Brick

Marcus the first post is kinda long and no paragraghs...guilty. but it's written in chronological order as to the events that set in motion. Basically I'm saying I have had number 1 for two years with the 70s and all stock and no issues swelling or killing plugs..
Number 2 truck has got a gremlin and the resistors on both trucks are ohming out the same. Ideas are apprediated...I'm not an English major. I included more info than necessary so I wouldn't have people saying to ohm the glowplugs ect. I have parts on the way...I will find it . I was just hoping it might spark a memory of a past repair someone else may have made that was similar.
I enjoy reading stuff on here and don't mind too bad how people relay it. My apologies for the lengthy explanations. Good day

The lengthy explanation isn’t the issue.
Not at all.

The difficulty is in reading what is basically a giant run-on sentence with zero paragraphs.

Do everyone a favor and break it up a bit.

Matt thanks for the private email message. I do have a resistance reading off the resistor bank.
It starts out at a reading of .4 ohms then .3 ohms finishing al 0 ohms over about 5 secs of test time. Both trucks do the same thing. And they are disconnected at the buss bar and at the top of the relay when measuring.
I am measuring through the wire and fusible link while not including my fingers in the circuit.
It's till attached to firewall but it doesn't seem to matter...I get same readings both ways off of both trucks. I have new plugs on the way but wont have time to work on it since I have to attend a funeral. Thanks for your time.

Awesome informative video on how a stock cucv glow plug system is supposed to behave:

https://m.youtube.com/watch?v=MTkOl947aTk

You CAN get a cascading failure with the stock setup. With each glow plug that fails the voltage ramps up on the remaining working plugs, causing more to fail. May be the culprit behind the under hood smoke. There's a way to bypass the resistor pack that works for some guys. But, when I tried it my system behaved like the low voltage part of the above video, except my gp's didn't shut down at all after startup, and didn't really show power draw on the voltage gauge. I kept my system stock and I'm just gonna test it periodically to make sure to avoid cascading failure.

I did Bosch glow plugs as well, you do need to change the spade connectors to a fatter one. Once thats done though you can run Bosch or AC60s. Both are self regulating, but I've heard mixed things about Bosch after the fact, and almost nothing but high praise for the AC60s. My next plugs will likely be AC60s. Same deal as you too, barely started in the 40s with the old plugs, starts like a champ in the 20s with the new ones.

Oh! DO check to make sure your glow plugs are authentic. There should be directions on the boxes on how to do that complete with an 18 digit code, with the remaining 6 digits in holographic text a 2nd time. Apparently there's been a running problem with fake Bosch equipment floating around.

LastFbody said:

May be the culprit behind the under hood smoke.

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Smoke is probably fusible links.

LastFbody said:

There's a way to bypass the resistor pack that works for some guys. But, when I tried it my system behaved like the low voltage part of the above video, except my gp's didn't shut down at all after startup, and didn't really show power draw on the voltage gauge.

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You might have had other problems that needed to be fixed, or, possibly, you didn't do it correctly. If it's done right, it works. Period. But, your current method works, too.

I think it didnt work for me because my front battery is somewhat weak. Might also have needed to replace the relay.

This has me thinking of two more "idiot lights". One would be parallel to the ballast resistor and only illuminate with voltage under 10 volts so when a glow plug fails, it will illuminate. The other idiot light is parallel to the glow plug relay so you know when the glow plugs are active. I think I can get voltage sensing LEDs in the range needed. Color red for the ballast resistor and yellow for the glow on indicator.

I always watch the voltmeter on startup so I know when the after glow is cycling.

90Jimmy said:

Ordered a set of Wellman on line, they showed up marked Diesel RX. RX70 on each plug. Called the vendor and he assured me that these are the same glow plug and they will not be marked Wellman. I did a little research and he was correct. Maybe a buy out or something. I did let him know it's misleading to use glow plugs marked Wellman in all sales photos...

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Interesting. I bought glowplugs for my military generator from DieselRX and they are made by Wellman. 24 volt 7/16" x 20 tpi thread. Not NOS so these must be OEM that are repackaged. It happens. Many OEM units lack manufacturer marks .

Got a chance to work a little. I'm in process of pulling the inner fenders...got left side done....to remove two stubborn glowplugs that swelled. I will post on my progress though it will be slow.
Also if anyone gets the time let me know the resistance of your glowplug resistor on firewall.
I'm thinking the 28 ohms in the book might be wrong. Thx

bryfor said:

Got a chance to work a little. I'm in process of pulling the inner fenders...got left side done....to remove two stubborn glowplugs that swelled. I will post on my progress though it will be slow.
Also if anyone gets the time let me know the resistance of your glowplug resistor on firewall.
I'm thinking the 28 ohms in the book might be wrong. Thx

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You are correct, sort of. 28 is wrong. It's 2.8. Two point eight. Not twenty eight.

Ahhh, but what's a decimal place among friends?