Fan Switch ... and ... ABS?

[SeventyMach1]

Well, I have my truck apart today ... so I was forced to drive the Stang (I know ... shame on me) to go get the part I needed.


Temps. were hot today and I was creeping past 195* on the road and some around 205*. So I flipped on the high speed fan switch that I installed a long time ago and let her get back down to around 180* -ish. Well, once I flipped the switch off, the car stumbled for a split second, I saw the speedo needle jump way down, then back up. This all happened like instantaneously. Almost too fast to see it happen. While this happened, my ABS light came on for a second or 2.


So ... I did it again (flipped switch on and back off). It does it again! I did this several times and this happens everytime I cut the switch off.


Is it something crazy going on with the ABS stuff or what? I have not tried to pull codes yet ... just seeing if anyone may have had this happen to them.

 

[HISSIN50]

Justin, I'd start by checking your battery and PDC connections.

Good luck bud.

 

[SeventyMach1]

Justin, I'd start by checking your battery and PDC connections.

Good luck bud.

May I ask why?



EDIT: JT, I didn't mean to be offensive there, lol. Just wondering what went through your head when you said that. Well, that wasn't tactful, either. You know what I mean, lol.

 

[HISSIN50]

May I ask why?

Yes you may. I might not say why though.

Justin, I thought you might have had a borderline connection with your primary load wiring and the jolt of high speed (it is a decent one) illuminated the poor connection. The ABS light can come on if it loses accessory power or power dips below 10 volts. I thought these two things might tie together (it was the one commonality I could think of at first blush. It could very well be wrong but I figure it's so easy to check............ ).

Now if there's an actual ABS code, that could help us out here.

I was trying to think of what else a load (I might assume the fan or about any other large load could cause it - remember our fans can have a start-up surge of 75 amps +. This lasts for milliseconds) could disrupt those systems, and as long as the ground pathway is good (we assume yours to be - the car has a nice home), I wasnt coming up with much else.

Good luck Justin.

EDIT: regarding your edit, no worries Justin. I don't know what I was thinking when I read half my replies either. I also like to have some sort of clue where someone's head was when they reply to my threads. Helps with those ideas from left field.

 

[SeventyMach1]

I am going to go throw some parts at it and see if that helps.








Haha, j/k. Thanks JT ... if I get the chance tomorrow after messing w/ my truck I will go check it all out, check for codes, wiring issues, etc. and post back up what I find.

 

[SeventyMach1]

Well, turns out ... bad battery AGAIN! It was a red top Optima, too! I just took it in to get a new one, as it has a 3 year warranty.

I just purchased it new in April of last year. The several people I have talked to say these batteries NEVER get switched out before their 3 year period is up. And, this is the 4th battery I have put into the car in the last 5 years (or something like that).


Car starts everytime with the new one and runs perfect. The car doesn't do the stutter thing when I turn the fan off now, either.


You think there could be something wrong making my batteries go bad? Or do I just have bad luck?

 

[HISSIN50]

Justin, I have heard of a few Optimas having issues lately (I dont know if it was red or blue - I'm only pretty sure that it was yellows). Maybe you just got a bad one.

I'm glad you got it figured out. Your problem was screaming load-side current issue to me when I read it initially. I didnt actually think it'd be your battery [itself] if the car had enough deep cycle to crank strongly however. You were wise with your diagnostics to not overlook anything.

.

 

[SeventyMach1]

It was very crazy. Optima's are very different. I guess more CCA's? Dunno, but it still would start good at times. I had to jump it a few times in the last week ... but I figured it was because it had just been sitting for so long.


Anyway, with it starting on it's on, I didn't think the battery was at fault either.


Then again, BOTH of the batteries were bad in my truck last year, and it was starting fine.