Temp Gauge??

TrickLidz · #1 (**permalink**) 10-18-2009, 11:13 PM

1998 748. Key ON temp gauge pegs to full HOT and stays there. (bike is cold and has not been run). Key OFF gauge goes back "0". Voltage at coolant temp sensor shows 6.5V.
Any ideas?

TrickLidz · #2 (**permalink**) 10-19-2009, 04:38 PM

Anyone??

G8RDuc · #3 (**permalink**) 10-19-2009, 04:57 PM

Quote:

Originally Posted by TrickLidz

Anyone??

It's either the gauge or the sender...I'd start with the sender since that's more likely.

TrickLidz · #4 (**permalink**) 10-19-2009, 06:47 PM

How do I test the sender??

G8RDuc · #5 (**permalink**) 10-19-2009, 06:49 PM

I'd just replace it...

DukeDesmo · #6 (**permalink**) 10-19-2009, 07:14 PM

Taken from workshop manual;

TrickLidz · #7 (**permalink**) 10-19-2009, 10:21 PM

thanks. How about a test for the single wire sensor that feeds the gauge only??

DukeDesmo · #8 (**permalink**) 10-19-2009, 10:33 PM

If single wire then test resistance between body (ground) and wire.

TrickLidz · #9 (**permalink**) 10-19-2009, 11:04 PM

thanks, will do. seeing as my gauge pegs to full hot when I put the key ON...I'm thinking the wire from the gauge to sensor is shorted to ground somewhere! Right?
I get less than 12v at the sensor wire.

TrickLidz · #10 (**permalink**) 10-19-2009, 11:12 PM

Attached Images

I understand that the sensor (top of diagram, orange/black wire) should ground to the housing where it's threaded, correct. Then why does it not show it going to ground in the diagram? Like the starter solenoid?
I may have too much sealant around the threads (I had a different sensor there when I used my digital dash for the track, so I'll check that.)
I quess my main question is- grounded wire will send the gauge to FULL HOT---open wire- gauge does not move??
TIA
'Lidz

DukeDesmo · #11 (**permalink**) 10-19-2009, 11:37 PM

Quote:

Originally Posted by TrickLidz

I quess my main question is- grounded wire will send the gauge to FULL HOT---open wire- gauge does not move??

According to the spec in the manual; lower resistance = higher temp, so a directly grounded sender wire would give full temp. It does sound like the sender is no good, which is 'good' news as it must surely be a cheaper fix than a new gauge.

TrickLidz · #12 (**permalink**) 10-19-2009, 11:51 PM

I too would think that the sensor is NO GOOD....BUT...the gauge pegs full hot with the wire removed from the sensor also!!

vij · #13 (**permalink**) 10-20-2009, 07:55 AM

Deleted

TrickLidz · #14 (**permalink**) 10-20-2009, 04:47 PM

Thanks ALL.
Found the problem...BIG Ahaaa moment!!

Decided to take the gauges off and check the back for the proper connections....and...sure enough the water temp connections were ass backwards!! I had removed them and reinstalled in the wrong places

Here's how they should be connected (if anyone cares at this point)

Thanks all!!!
'Lidz

TrickLidz · #15 (**permalink**) 10-20-2009, 04:48 PM

Damn, sorry for the HUGE pic!!