Heat related voltage drop
Thread Starter
Intermediate
Joined: May 2021
Posts: 28
Likes: 2
From: Ormond Beach FL
Heat related voltage drop
2006 Z51 convertible, 105000 miles
How do I diagnose the radiator fan controller? When the engine is up to temp and I'm in traffic the externally connected VOM drops to 13.1 volts. The DIC shows 12.4 volts.
I have checked continuity and resistance on every wire I can reach and all checkout. I have a new starter, battery and alternator. Appearing to be a heat related problem, the temp controls are my next target.
Any suggestions or recommendations appreciated?
How do I diagnose the radiator fan controller? When the engine is up to temp and I'm in traffic the externally connected VOM drops to 13.1 volts. The DIC shows 12.4 volts.
I have checked continuity and resistance on every wire I can reach and all checkout. I have a new starter, battery and alternator. Appearing to be a heat related problem, the temp controls are my next target.
Any suggestions or recommendations appreciated?
Melting Slicks
Joined: Apr 2010
Posts: 2,790
Likes: 108
From: On the coast North of SF bay
Need a more robust description of what the issue is. What is causing you to look at this? Are the fans not working, or? 13.1 doesn't seem to be a "drop" and where is the VOM connected???
Nick
Nick
Thread Starter
Intermediate
Joined: May 2021
Posts: 28
Likes: 2
From: Ormond Beach FL
I had the VOM connected to the battery hot post and the neg on a chassis ground. Thats how I got the two numbers. I got the "check charging system" warning awhile back so I replaced the starter, the battery and the alternator.
Out on the road I see 13.9 to 14+ on the DIC but when in traffic it gradually goes down to less than 13 into the 12-volt range. My understanding is it should never go below 13.5. The engine temp is always normal.
I would not be chasing this problem if I had not got the service charging system warning. For now, I'll wait for something to stop working so I can pinpoint the issue. The DIC is not reading correctly. It is 0.3 volts lower than the VOM. I'm going to add 0.3 to whatever the display is and move on.
Out on the road I see 13.9 to 14+ on the DIC but when in traffic it gradually goes down to less than 13 into the 12-volt range. My understanding is it should never go below 13.5. The engine temp is always normal.
I would not be chasing this problem if I had not got the service charging system warning. For now, I'll wait for something to stop working so I can pinpoint the issue. The DIC is not reading correctly. It is 0.3 volts lower than the VOM. I'm going to add 0.3 to whatever the display is and move on.
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,642
Likes: 4,082
From: Cape Coral, Florida
I had the VOM connected to the battery hot post and the neg on a chassis ground. Thats how I got the two numbers. I got the "check charging system" warning awhile back so I replaced the starter, the battery and the alternator.
Out on the road I see 13.9 to 14+ on the DIC but when in traffic it gradually goes down to less than 13 into the 12-volt range. My understanding is it should never go below 13.5. The engine temp is always normal.
I would not be chasing this problem if I had not got the service charging system warning. For now, I'll wait for something to stop working so I can pinpoint the issue. The DIC is not reading correctly. It is 0.3 volts lower than the VOM. I'm going to add 0.3 to whatever the display is and move on.
Out on the road I see 13.9 to 14+ on the DIC but when in traffic it gradually goes down to less than 13 into the 12-volt range. My understanding is it should never go below 13.5. The engine temp is always normal.
I would not be chasing this problem if I had not got the service charging system warning. For now, I'll wait for something to stop working so I can pinpoint the issue. The DIC is not reading correctly. It is 0.3 volts lower than the VOM. I'm going to add 0.3 to whatever the display is and move on.
Last edited by C5 Diag; Sep 4, 2022 at 07:25 PM.
