2005 Liberty, CEL code 1261. Replaced the number 1 glow plug with with a Bosch 5 volt. Bad plug was metallic. CEL still on. Controller is a 56044671AA. Does this need to be replaced with a 56044671AC? Does the ECU need reprogramming also?

The Glow plug harness might be installed backwards, therefor coding for the wrong glow plug !!!!

You can to test the GP for resistance at the connector , new one are less than 1 ohm, used one should be less than 5 ohms.

The swapped harness is a fairly common thing to run into I believe the last plug on the glow plug harness goes to number one glow plug but I could be misremembering. You could swap harness connection between number one and number two and if code doesn't change to 1263 with original plug then it is on backward and number 4 cylinder has the bad glow plug. It would be unusual to be the controller but if it is the bad code should change to 1263 unless harness is backward then it would still stay with cylinder 4.

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05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 195K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 210K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 126K wkII Eur TC
05 D khaki Lim 145k refurbishing
All CRDS: Fumoto, Lift , Fan Shroud mod, fuel head Gen II, SAMCOS,self TB, 2 Mic filt, Hayden

I may have misunderstood part of your question. The original controller for 7 volt glow plugs can be used with 5 volt glow plugs also and in fact should give better starting in cold weather.

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 195K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 210K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 126K wkII Eur TC
05 D khaki Lim 145k refurbishing
All CRDS: Fumoto, Lift , Fan Shroud mod, fuel head Gen II, SAMCOS,self TB, 2 Mic filt, Hayden

perhaps an easier way to check.

If you have a code - indicated glow plug failure, and can get to that plug lead, pull it off of the plug, and try it again.
If there is no change in code, the harness is on correctly.
If there is any change, (additional or different code) then the harness is on backwards.

_________________
'06 Lbrty Sprt CRD 150K

Sasquatch
DSS Turbo
CAT-elimntr
Weeks Stg1&2 EGRfix
PV-200
BLING
vent gauges

IDParts
head
cams
rockers
Timing set
ARP studs
eTn1 GX2123 5v GPs

YETI Custom Tune
Flowmaster 8325508
Carter P76611M
GM 12611872
Hayden 2986
GM 15976889
PATC Custom Billet
2010 Ram Hemi Trans
Sonnax 44957
Transgo kit
Cooper 51770

I thought about that and if it is on backwards that is definitely easier. I was trying to also show whether or not controller had a problem. I still may or may not do that with my check. If code didn't change to 1263 then either controller is problem (which could be by bad connection etc.) or the replacement glow plug was also bad. I may be mixed up now since not thinking too clearly this am.

_________________
05 Blu LIM, OME GDE Tbo, wk II 245/75/17, KC Lights, bull bar, 195K H TC
05 Blu Lim, Dayton, GDE HT, 255/75/18 , 210K , H TC
06 Bla Lim, GDE Eco, Destination AT 245/75/17, 151K, H TC
06 D Khaki Lim 126K wkII Eur TC
05 D khaki Lim 145k refurbishing
All CRDS: Fumoto, Lift , Fan Shroud mod, fuel head Gen II, SAMCOS,self TB, 2 Mic filt, Hayden

If the controller is bad, none of them should work. The PWM switch affects all equally if they are a proper set.

_________________
'06 Lbrty Sprt CRD 150K

Sasquatch
DSS Turbo
CAT-elimntr
Weeks Stg1&2 EGRfix
PV-200
BLING
vent gauges

IDParts
head
cams
rockers
Timing set
ARP studs
eTn1 GX2123 5v GPs

YETI Custom Tune
Flowmaster 8325508
Carter P76611M
GM 12611872
Hayden 2986
GM 15976889
PATC Custom Billet
2010 Ram Hemi Trans
Sonnax 44957
Transgo kit
Cooper 51770