Temperature Gage (or other) Not Working

[Chavez1978]

I tried searching and can't find any specifics, but I'll post what I've done thus far.

Boat seems to run at normal temps, but my gage doesn't ever move off far left....doesn't pick up the reading. I changed out one of the temp sending units as it was broken thinking that was the issue. Still nothing. I've taking both wires off the terminals and swapped them side to side on each sending unit...still nothing.

What would be my best troubleshooting steps next according to you pros out there...? Been trying to do the simple things first.

thanks,

chay

 

[achris]

Re: Temperature Gage (or other) Not Working

Does the gauge peg when you ground the sender wire?

And what are we working on, a Massey-Ferguson tractor? Bit more information will get you a lot more answers...

 

[Chavez1978]

Re: Temperature Gage (or other) Not Working

I've yet to see the gage move which leads me to think I've got a short, bad or incomplete connection or a bad gage.

It's a 5.7L Mercruiser

 

[achris]

Re: Temperature Gage (or other) Not Working

Does the gauge peg when ground the sender wire?

Merc have been using 5.7 litre GM blocks since 1977, so that doesn't help much... How about a year or an engine serial number....

 

[Oshkosh1]

Re: Temperature Gage (or other) Not Working

Have a read at this...may clear up some basic communication/info issues.
http://forums.iboats.com/showthread.php?t=220416

 

[Chavez1978]

Re: Temperature Gage (or other) Not Working

Thanks Oshkosh. My bad

 

[Chavez1978]

Re: Temperature Gage (or other) Not Working

I ended up scabbing a wire to ground the other sending wire, and sure enough it pegged out the gage...so I'm guessing I have a bad sending unit on that side. I didn't realize that one was for the gage, the other I'm assuming is for audible alarm.

For sake of completeness, Engine is a Mercruiser 5.7L 350 MAG ALPHA w/ engine serial OF438792

 

[achris]

Re: Temperature Gage (or other) Not Working

I ended up scabbing a wire to ground the other sending wire, and sure enough it pegged out the gage...so I'm guessing I have a bad sending unit on that side. I didn't realize that one was for the gauge, the other I'm assuming is for audible alarm.

For sake of completeness, Engine is a Mercruiser 5.7L 350 MAG ALPHA w/ engine serial OF438792

Yes.

 

[Silvertip]

Re: Temperature Gage (or other) Not Working

And make sure you end up with a temperature "sender", not a temperature "switch" -- there is a difference.