OK!
Clinical Assessment Only Of Original Post. Quote:
Originally Posted by DuaneD  Ok, now with the fuel sending work we are onto the reverse switch mounted on top of my T-176 tranny case. |
OP has established the transmission is a T-176.
------------------------------------
Quote:
Originally Posted by DuaneD A lot of the times the reverse lights stay on all the time. |
This would be the 'Issue' the OP is having.
-------------------------------------
Quote:
Originally Posted by DuaneD Sometimes the lights are off when moving forward. |
This would be CORRECT operation of the switch.
(reverse lights 'OFF' when vehicle is NOT in REVERSE)
--------------------------------------
Quote:
Originally Posted by DuaneD I unscrewed the switch with a 15/16 socket. |
Standard Reverse Light Switch size.
Good to know he removed the switch and tested it free of transmission 'Ground'.
Shows good testing procedures and practices.
---------------------------------------
Quote:
Originally Posted by DuaneD Bench tested it and got a closed circuit of 7 ohms. |
7 Ohms is too high for a closed circuit in just the switch.
You will ALWAYS read some resistance in a 'Closed' switch, but 7 Ohms would classify the switch contacts as a RESISTOR around here.
Obviously there is something
WRONG inside the switch,
Carbon, Corrosion, Moisture, Dehydrated/Hardened Lubricants are interfering with the switch contacts if it's showing 7 Ohms resistance on the bench when 'Closed'.
------------------------------------
Quote:
Originally Posted by DuaneD Screwed the switch back in, hooked up the DVM, and got in the range of 85-90 ohms (with the tranny in reverse, out of gear we infinite overload). |
OP states that switch was screwed into the case...
He DOES NOT state if the wiring connections were made or not.
With connections made, 85 to 90 Ohms would be about correct with the tail lights in the circuit.
Without connections made, the
ONLY REASON resistance would have increased is something inside is moving around and getting in between contacts when the switch tries to 'Close'...
*IF*...
It's a SINGLE post switch, there isn't proper 'Ground' between swtich and case.
If it's a DUAL POST switch, (and most are) the switch has serious internal problems that can't be repaired in any meaningful or cost effective way.
*TURNED OUT TO BE A DUAL POST SWITCH IN A LATER POST BY THE OP...* Quote:
Originally Posted by DuaneD No, we are testing between the two pins on the switch... |
----------------------------------------------
Quote:
Originally Posted by DuaneD Is this reasonable, right, wrong, or a switch bad? |
I would say Jim_Lou answered the question,
But just for the spectators that can't keep up with the conversation...
The switch is doing strange things, and therefore classified as 'BAD' and should be replaced...
----------------------------------
Quote:
Originally Posted by DuaneD The red and white pig tail was not connected when we check this resistance. |
This information would have been more helpful further up in the post, but it's good to know.
This makes the 85-90 Ohms totally unacceptable.
-----------------------------------
Quote:
Originally Posted by DuaneD What do you think? |
What I 'Think' is irrelevant, but thanks for asking...
The switch is 'BAD'.
It's probably as old as the vehicle/transmission, that would be 24 years of service, time for a replacment.
-------------------------------------------
NOW... ARE YOU READY FOR THE FIRST ANSWER IN THE THREAD....? Quote:
Originally Posted by Jim_Lou Replace the switch - it's not expensive. |
I concur.
Under $15 for a quality piece, and easily sourceable from about any of the jeep places and parts stores.
-------------------------------------------
NOW, ARE YOU READY FOR THE SECOND OPINION/ANSWER IN THE THREAD...? Quote:
Originally Posted by TeamRush Jim is correct, you should be showing about 1 Ohm or less when the trans is in reverse.
And you should be showing 'OVER LIMIT' resistance when the trans IS NOT in reverse...
Sounds like the switch has given up internally. |
---------------------------------------------------------------
OP's 'ISSUE' is resolved in this post from the OP...
REPOSTED HERE, for those that 'Missed' it! Quote:
Originally Posted by DuaneD Thank you guys.
I appreciate you taking the time to share some of your wisdom.
I have ordered a new backup Light Switch for my T176 tranny, part #52449.0252 from Quadratec at $12.99.
I will check resistance values of the new switch, compare to the old, and report back. Thanks  |
---------------------------------------------
Since the OP's 'Issue' was resolved... The conversation then progressed to what constitutes an 'Open' circuit,
'Closed' circuit,
And what could the 'Average' switch would read with the common, cheap, hand held DVM... There IS NO SUCH THING AS 'ON' and 'OFF' as absolutes in common automotive switches...
There are 'Thresholds' where the switch isn't passing enough current to operate any given device ('Off') and when the switch is passing enough current (with resistance) to do the job it's intended to do ('On').
ALL Automotive switches will show some resistance when 'Closed',
And all automotive switches will show continuity when they are 'Open'...
This was a REAL PAIN for early computers/digital equipment, but the 'Variances' have been accounted for now.
The 'WISDOM' the OP spoke of was finding out that automotive switches DO show resistance and continuity when they 'Ideally' shouldn't.
EVERYONE WORKING ON ELECTRICAL SYSTEMS SHOULD KNOW THIS... 
Linear Mode
