Hot Rod Forum : Hotrodders Bulletin Board - View Single Post - need help with a 12 v to 6 v reducer
View Single Post
  #5 (permalink)  
Old 06-17-2006, 09:25 AM
oldguy829's Avatar
oldguy829 oldguy829 is offline
Last wiki edit: Swapping to rack and pinion steering
Last journal entry: 53 coupe
Last photo:
Join Date: Sep 2005
Location: San Antonio Tx
Age: 73
Posts: 565
Wiki Edits: 88

Thanks: 0
Thanked 0 Times in 0 Posts
12 v to 6 v reducer.

Doc. I need to chew on this a little, but i think I get it.

1. Didn't expect the sender to work right, but thought it would move in some relationship to reality until I could get the right sender. (the parts guy said all senders work in a "similar range", which I now see is bogus)

Yes, I rechecked the function of the voltage reducer, and when I read it after it passes thru the gauge, it is about 9 volts. Do I need to do something to get this down to 6? I also tested the one that supplies the gas gauge, it also reads about 9 volts. If I wire the 2 in series, would that work?

2. not sure I can run the first test, because it just pegs at all temps. Or maybe you didn't intend for me to do that test until I had a gauge that worked.

3. the test for value. OK there, except for the "reverse" part, (if the sender has less resistance than is required) . the gauge only has 2 wires. the hot lead and the sender. I think you are saying to put the resistors between the gauge and its ground, which I can't do easily, cause it grounds to the dash. But we can cross that bridge if we come to it.

4. As a starting point - with the 0 meter set at 20k the sender appears to have a resistance of .15 the gauge had a resistance of .06 Neither hooked up to anything, just a "unit" test. Maybe this is irrelevent.

It just seems that if the gauge pegs when connected [it starts out on the low side and steadily moves to the high temp side to totally pegged within about 10 seconds] would'nt that indicate the sender has less resistance than the gauge ?

Which is opposite those "unit test" numbers. Or I'm thinking *** backwards. Likewise, if I ground the sending unit wire, it pegs the needle. that is 0 resistance right?

So more resistance in the sender line seems to be the answer, except for that "unit" test. So tell me that was a BS test and to ignore that, and I think I have my mind right.

5. The big question. Assuming I can figure all this out, how do i find the right sender? I can only imagine the look I'm going to get when i walk in and ask for a sending unit from 30 to 60 ohms? The usual response is "what make and model car is that for?"

Doc, I sure appreciate this help. Getting the original gauges to work properly just seems like the right thing to do. don

Last edited by docvette; 06-17-2006 at 03:42 PM. Reason: edited for ease of sorting
Reply With Quote