Does anybody know where G150 goes?
For some reason, it may be important that G150 is grounded to the same stud as G103.
Good question. I went through all 4 volumes of the '98 FSM, and also checked the '99 FSM too.
To be honest, it looks like the "G150" ground is part of the noise floor of the service manuals?
That is, it is an error in that illustration that wasn't caught during final proofreading?
To convince myself that the G150 reference was a mistake, I scanned Vol. 1 of the '98 FSM
for how many times that each of the following grounds are referenced, whether in the DTC
troubleshooting flows and/or in the wiring diagrams.
Ground - total number of references:
G103 --- (30)
G104 --- (35)
G105 --- (25)
G150 --- ( 2)
In essence, the G150 we saw in the illustration was not seen elsewhere in the troubleshooting flows.
To build confidence in the above, I decided to Search the entire GMT400 forum for these same
grounds and count how many replies contain them:
Ground - total number of replies
G103 ---
( 28)
G104 --- (
29)
G105 ---
( 31)
G150 --- (
6 3) Note: 3 are from
this thread. The other 3 are from another thread that dead-ended prior to a successful resolution.
Given the above, I suggest that for now we should sideline any references to 'G150'.
NOTE: Circuit #150 is used to document the wiring of several ground circuits in the FSM, so it's possible that G150 was
a naming error taken from a ground circuit #? (See 1st attachment) Which in turn begs the question - if there's actually
a 3rd ground wire in the vicinity, what would it's proper name be?
To summarize, G103/104/105 are legitimate grounds, regularly referenced in DTC descriptions and troubleshooting flows.
G150 looks to be an orphan entry in an illustration in the '98 FSM. (See 2nd & 3rd attached for differences between '98 & '99
454 ground illustrations.)
That's all I've got. If anyone can find a legitimate reference to G150 in the FSMs then
please don't hesitate to add it here. (I consider myself a student of the FSMs and I'm
still learning them myself.)
FWIW --