Expert: Roland Finston - 7/17/2011

Question
QUESTION: hi roland
looked thru past questions to last Oct didnt see this one. 40 amp fuse blowing takes out turn signals power remote door locks abs and ac blower motor. looked at pdc and do not see anything unusual even turned it over and checked plugs. rear lights working ok. have you seen this? found some other people with same problem but did not see how it was resolved.used dvm on pdc looked for resistance to be same at all 40 amp connection w/o battery then with battery checked for voltage.tried moving relays around. gone through 3 fuses and here in columbus oh stores are very low on 40 amp fuses. got 2 left  help  
thanks roland
joe

ANSWER: Hi Joe,
I assume that the '98 wiring diagrams I have apply to your '00 and that you have a separate fuse box under the dash and a power distribution box under the hood. There are 8 40A fuses under the hood and so I wonder which one is blowing. I see # 21 applies to the blower, and 25 to the ABS, and a smaller fuse 10 applying to the turn signals. And I see fuse 12 under the dash applies to all three of those systems and it is 10 amps. The remote keyless entry needs fuse 28 in the power distribution box and positive temp control device #3 under the dash. So I can't ID a single 40A fuse that takes out all four systems.
Please check and verify if you have a different set-up. The other manual I have is an '02 and it has just one large fuse box under the hood.
Roland

---------- FOLLOW-UP ----------

QUESTION: thanks for the reply Roland
the fuse is marked door locks seats right next to the abs.  when this fuse blows the door locks and abs and ac blower stop so i unplugged the blower motor and replaced the fuse and it took a while but it blew again.
with the new fuse in i still did not see turn signals so that may not be related. Looking like something in door lock system. I have a snap-on scanner and checked for codes on pcm and bcm. there was nothing. i do not see fuse numbers anywhere so i checked all under dash none bad. in pdc 20amp cig accessories was bad. the 40 is number 2 from firewall of the 8
thanks again
i am doing this for someone else and it is volunteer work so i appreciate what you are doing
joe

Answer
Hi Joe,
OK, it is fuse #26 and though 'obscure' I find that it does get involved with everything you said it did.
The fuse goes do the door lock motors (via a 9 amp fuse-like positive temp coeff device in the box under the dash), but then it also powers a 30 amp circuit breaker for the power/heated seats, and in parallel it also powers a section of the ignition switch when in the 'run' position it powers fuses 11 (20 amp, rear A/C unit) and 12 (10 amp, rear window defog relay, driver heated seat, turn signal flasher, abs controller, transmission range sensor, front blower motor relay, passenger heated seat) located in the box under the dash. Those two fuses though would together only draw 30 amp before blowing (unless someone put in larger fuses?). But the power door locks are also fed by the 9 amp positive temp coefficient device so that still only totals to 39 amps, so I am beginning to suspect the the 30 amp circuit breaker in the wire harness under the driver's seat is not 'breaking' when something about the power seat system is drawing more than 40 amps and thus blowing fuse 26. Or maybe the sum of all the current draws exceed 40 amps, which is possible I guess.  
I would start by disconnecting the 30 amp circut breaker for the power seats, and then see if that stops the problem with fuse 26. If not, then we have to figure out which of the many fuses I listed above has been by-passed or had a larger fuse substituted.
This is a pretty marginal circuit I must say to have so many different sub-circuit being powered out of 26 and the rather opaque wiring diagrams. Not typical Chrysler engineering from my point of view!
I will be very interested to see what you find.
Roland
PS: Please use the 'thank/rate' tab below, and where you see the question about a nomination of me to be 'volunteer of the month', consider a 'yes' response. Thank you  
Glad to hear you are also a 'volunteer'!