Glow plug module from 7v to 5v

Joelweb · **Posted:** Fri Jan 13, 2017 5:02 pm

From reading old threads it looks like the old ceramic 7v glow plug module might be the same as the replacement for the 5v metal plugs. Is this correct? I know that I need to re-flash my ECM if switching to 5v, but do I need to replace the module?

thanks

ebbnflow · **Posted:** Fri Jan 13, 2017 5:50 pm

The modules are the same, but it's not a bad idea to replace it when you replace the glow plugs. Check your harness from the module to the plugs also. It can deteriorate over time.

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

It depends on the version whether the modules are the same. All CRDs were manufactured with 56044671AA and was for the 7v plugs. The replacement part number is 56044671AC and is for either 5v or 7v plugs. Unless you have had the module replaced at some point you will have the old AA version and should probably change it for the AC.

jrsavoie · **Posted:** Sat Jan 14, 2017 1:36 pm

Ceearedeedriver wrote:

It depends on the version whether the modules are the same. All CRDs were manufactured with 56044671AA and was for the 7v plugs. The replacement part number is 56044671AC and is for either 5v or 7v plugs. Unless you have had the module replaced at some point you will have the old AA version and should probably change it for the AC.

What are possible ramifications of not changing the module?

The ceramics on my Jeep were changed out for 5 volt glow plugs with no other changes to anything made. It seems to start and run good. It has been this way for about 40,000 miles

I live in north east Illinois and it gets cold here

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

jrsavoie wrote:

Ceearedeedriver wrote:

It depends on the version whether the modules are the same. All CRDs were manufactured with 56044671AA and was for the 7v plugs. The replacement part number is 56044671AC and is for either 5v or 7v plugs. Unless you have had the module replaced at some point you will have the old AA version and should probably change it for the AC.

What are possible ramifications of not changing the module?

The ceramics on my Jeep were changed out for 5 volt glow plugs with no other changes to anything made. It seems to start and run good. It has been this way for about 40,000 miles

I live in north east Illinois and it gets cold here

The newer module has a higher current rating. The most likely issue not upgrading would just be module failure. At 10+ year old I'm hesitant to even use the word premature.

jrsavoie · **Posted:** Sat Jan 14, 2017 2:48 pm

Ceearedeedriver wrote:

jrsavoie wrote:

Ceearedeedriver wrote:

It depends on the version whether the modules are the same. All CRDs were manufactured with 56044671AA and was for the 7v plugs. The replacement part number is 56044671AC and is for either 5v or 7v plugs. Unless you have had the module replaced at some point you will have the old AA version and should probably change it for the AC.

What are possible ramifications of not changing the module?

The ceramics on my Jeep were changed out for 5 volt glow plugs with no other changes to anything made. It seems to start and run good. It has been this way for about 40,000 miles

I live in north east Illinois and it gets cold here

The newer module has a higher current rating. The most likely issue not upgrading would just be module failure. At 10+ year old I'm hesitant to even use the word premature.

On my old GMT400 6.5 diesels, I have glow plug controllers that are going on 25 years old and still working. They were built much better than these jeeps appear to be though.

I guess I'll just run until it fails, if all that will happen is module failure. With the poor quality of replacement parts anymore, I don't fix much that ain't broke. Seems the good old part might outlast the new replacement part in many cases

Sir Sam · **Posted:** Sat Jan 14, 2017 7:20 pm

FWIW I did not replace the module on my 05 and its been running on the new plugs for 1.5 years now without issue on the original module.

Joelweb · **Posted:** Sun Jan 15, 2017 12:15 am

Thanks, fellas. For $35 I went ahead and ordered a new Bosch module. Crappy time for a 7v glow plug to go. Negative temperatures around here. Time to just get it taken care of.

jrsavoie · **Posted:** Sun Jan 15, 2017 11:49 am

Joelweb wrote:

Thanks, fellas. For $35 I went ahead and ordered a new Bosch module. Crappy time for a 7v glow plug to go. Negative temperatures around here. Time to just get it taken care of.

I'd replace with the 5 volt Bosch Duraterms. Had good luck with Duraterms in the 6.5 diesels.

So far I wouldn't worry about changing to a 5 volt tune. I haven't heard of anything bad happening by running that way

Are the Bosch Duraterms for these self limiting? I need to remember to call Bosch and ask.

jrsavoie · **Posted:** Sun Jan 15, 2017 11:53 am

I wonder if there is a difference in the module or if the tune just limits the glow plug time for the 5 volt tune?

Should ask Kieth about the difference in the tunes. I think I wasted my money on the 5 Volt tune upgrade for my Green Eco tune.

viewtopic.php?f=5&t=85825&start=20

Ceearedeedriver · **Joined:** Fri May 06, 2016 8:44 pm **Posts:** 177

jrsavoie wrote:

I wonder if there is a difference in the module or if the tune just limits the glow plug time for the 5 volt tune?

Should ask Kieth about the difference in the tunes. I think I wasted my money on the 5 Volt tune upgrade for my Green Eco tune.

viewtopic.php?f=5&t=85825&start=20

The module is the same. The programming is supposed to provide different waveform for the two different plug voltages. But to add even more confusion the guys over on the DIY tune thread are suggesting that the Chrysler maps for 5V and 7V are identical!

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

jrsavoie wrote:

Ceearedeedriver wrote:

It depends on the version whether the modules are the same. All CRDs were manufactured with 56044671AA and was for the 7v plugs. The replacement part number is 56044671AC and is for either 5v or 7v plugs. Unless you have had the module replaced at some point you will have the old AA version and should probably change it for the AC.

What are possible ramifications of not changing the module?

The ceramics on my Jeep were changed out for 5 volt glow plugs with no other changes to anything made. It seems to start and run good. It has been this way for about 40,000 miles

I live in north east Illinois and it gets cold here

Jeffrey, with the successful installation of your Webasto heater, I really doubt that your glow plugs will ever need to come on again.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

Ceearedeedriver wrote:

jrsavoie wrote:

I wonder if there is a difference in the module or if the tune just limits the glow plug time for the 5 volt tune?

Should ask Kieth about the difference in the tunes. I think I wasted my money on the 5 Volt tune upgrade for my Green Eco tune.

viewtopic.php?f=5&t=85825&start=20

The module is the same. The programming is supposed to provide different waveform for the two different plug voltages. But to add even more confusion the guys over on the DIY tune thread are suggesting that the Chrysler maps for 5V and 7V are identical!

Well, that would scare me from using those tunes as the glow logic is very different between 5v and 7v glow plugs. They might be saying that if they do not know what they are looking at.

jrsavoie · **Posted:** Wed Jan 18, 2017 1:32 am

GreenDieselEngineering wrote:

Ceearedeedriver wrote:

jrsavoie wrote:

I wonder if there is a difference in the module or if the tune just limits the glow plug time for the 5 volt tune?

Should ask Kieth about the difference in the tunes. I think I wasted my money on the 5 Volt tune upgrade for my Green Eco tune.

viewtopic.php?f=5&t=85825&start=20

The module is the same. The programming is supposed to provide different waveform for the two different plug voltages. But to add even more confusion the guys over on the DIY tune thread are suggesting that the Chrysler maps for 5V and 7V are identical!

Well, that would scare me from using those tunes as the glow logic is very different between 5v and 7v glow plugs. They might be saying that if they do not know what they are looking at.

So are there any risks being run, using the 5 volt glow plugs on a 7 volt tune?

Mines been that way since I got the tune. Never was asked what I had for glow plugs back then. Didn't even know there were choices. Never had any choices in voltages for any other vehicle or machine I've ever had

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

The 7 volt logic will over juice the 5 volt plugs and shorten their lifespan. That would be the main risk.

geordi · **Posted:** Wed Jan 18, 2017 10:27 pm

Shorter lifespan could be OK if we are talking "many months" or "several years" instead of years or decades.

If it means they will be getting killed within a few months / one season, people will have to decide for themselves. Having the CRD start up easier with a hot plug may be worth the expense.

WWDiesel · **Posted:** Wed Jan 18, 2017 11:57 pm

I am not an electrical engineer, but some thoughts:
If you install GP's designed for 5v and apply 7v to them (without program change), the wattage will increase making the tips get hotter as they (5v GP's) would have somewhat less amps (resistance) across the tips due to their design for the lower voltage. How long they will last under these conditions is a matter of conjecture as the element in the tip will eventually fail depending on how much time they are in actual service.

If I were going to install 5v GP's on a 7v system, I believe I would investigate adding a resistor of some sort in the power supply to the GP's to help offset the higher voltage...thus lowering the wattage. Would take some testing to get correct! :roll:

We used to do this all the time to continue using some 6v equipment on 12v systems when converting older vehicles from 6v to 12v...it worked like champ!

Remember, Watts = VOLTS x Amps
If you raise the volts and the amps are the same (5v versus 7v), the watts will go UP!
So I guess it begs the question, what is the difference in resistance between the 7v and 5v glow plugs....

jrsavoie · **Posted:** Sun Jan 22, 2017 12:01 pm

I have been running 5 volt glow plugs on a Green Diesel Eco tune of about 40,000 miles now. I didn't have a clue what I had for glow plugs Until I started reading glow plug threads about the possible ramifications of running the OEM ceramics.

We were given a set of glow plugs by a dealer, but had no idea there was more than one voltage or even type of glow plug available at the time.

Has anybody ever had swelling tip issues with the Bosch 5 volt plugs?

viewtopic.php?f=5&t=86001

Glow plug module from 7v to 5v

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