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I have a '96 ZF-6 with no reverse lights. The trans was recently purchased used and came with a Hurst shifter already installed.
Everything works great, but I have no back-up lights. Jumpered the switch plug and the lights work. Pulled the switch and it makes contact with the ball depressed about 1/8"
I checked the plunger in the trans for movement in and out of reverse gear and it does not seem to move out enough to push the ball enough to close the switch. The switch is fully seated.
Is there an adjustment on the shifter linkage (or elsewhere) that will change this?
By the way, I found a great tool to remove the switch: a crowfoot style oxygen sensor socket. 7/8" socket extended just the right amount with an offset 3/8" drive square hole. Rented it from Autozone.
The trans was recently purchased used and came with a Hurst shifter already installed.
There are two different types of switch/plunger that with thread in your transmission and look almost exactly alike with one being about 1/4 inch longer.
Since the trans is used, the correct unit may have been swapped?
I made the mistake of buying a switch and found that I needed the longer version. BTW, parts stores will not carry the longer switch (which comes with a pigtail) and you need to order it. Try Eklers.
There are two different types of switch/plunger that with thread in your transmission and look almost exactly alike with one being about 1/4 inch longer.
Since the trans is used, the correct unit may have been swapped?
I made the mistake of buying a switch and found that I needed the longer version. BTW, parts stores will not carry the longer switch (which comes with a pigtail) and you need to order it. Try Eklers.
There is only "ONE" switch for the ZF - there ain't no short or long - the after-market service part has a pigtail that requires adaption to the car but threads/detent etc is the same I believe. I have never used the switch offered by the after-market so if you've anything other than OE/GM maybe there's issues.
OP - I've never experienced your issue and I'd suggest you just soak it, exercise it and reinstall. I believe that all except 2 after a soak and exercise have functioned. Best I recall they weren't interested in the effort and just tossed them. Did it happen to have a washer on it?
I thought I had an NOS here and I was going to count threads and confirm length. I can't put my hand on it.
No washer.
No pigtail so I thought it was OEM. The trans was purchased from a GM dealer new and run in a race car for a short time so maybe the back-up lights never worked and no one noticed or cared.
The switch might not have ever been connected before I got it.
The switch works fine on the bench, but when I screw it in with the transmission in reverse I should feel resistance just before it seats. Instead, it turns in freely until it gets tight.
I think I'll order a new switch and compare the two.
No washer.
No pigtail so I thought it was OEM. The trans was purchased from a GM dealer new and run in a race car for a short time so maybe the back-up lights never worked and no one noticed or cared.
The switch might not have ever been connected before I got it.
The switch works fine on the bench, but when I screw it in with the transmission in reverse I should feel resistance just before it seats. Instead, it turns in freely until it gets tight.
I think I'll order a new switch and compare the two.
Might be interesting to check with a "bore scope" - I had never had any interest but there you are with maybe an excellent reason to get inquisitive!!
Might be interesting to check with a "bore scope" - I had never had any interest but there you are with maybe an excellent reason to get inquisitive!!
I used a mirror and can clearly see the part that should engage the ball in the switch. I also held an allen wrench against this part while my son worked the shifter in and out of reverse. This part moves in and out, but not a by much. Maybe there is an internal issue with the transmission.
I looked at a picture of the aftermarket switch Ecklers sells and it appears to have the same number of threads.
There is only "ONE" switch for the ZF - there ain't no short or long - the after-market service part has a pigtail that requires adaption to the car but threads/detent etc is the same I believe.
I just did this repair about six week ago. Agreed that there is only one to fit the ZF, but the parts houses show that two will fit- hence how I bought the wrong one.
The pigtail is clearly an aftermarket mod but seems to be pretty common- it made it MUCH easier to install There was no adapting on my car, only a bit of wiring loop that I zip tied securely.
So, purchase at your own risk. For me the factory one was longer shaft, the first purchase (showing the correct part number) had a shorter threads and the pigtail with the longer threads was just right. There is no way to make an internal mod to the transmission.
Agreed that there is only one to fit the ZF, but the parts houses show that two will fit- hence how I bought the wrong one.
The pigtail is clearly an aftermarket mod but seems to be pretty common- it made it MUCH easier to install There was no adapting on my car, only a bit of wiring loop that I zip tied securely.
So, purchase at your own risk. For me the factory one was longer shaft, the first purchase (showing the correct part number) had a shorter threads and the pigtail with the longer threads was just right.
Maybe a wrong switch was used in this transmission before I got it. I don't think this one would have to be much longer to work. You are saying that the first one you got did not have a pigtail?
The Ecklers one seems to have the same number of threads as the one I have, though the picture is not clear enough to be 100% sure.
I have a bad switch. My ohm meter has a tone setting and though the switch would sound the tone, it reads around 30-40 ohms.
I plugged the switch into the car and pressed the ball: no lights.
Jumped the plug: lights.
I flushed it with contact cleaner several times but no change.
I have a bad switch. My ohm meter has a tone setting and though the switch would sound the tone, it reads around 30-40 ohms.
I plugged the switch into the car and pressed the ball: no lights.
Jumped the plug: lights.
I flushed it with contact cleaner several times but no change.
I have a bad switch. My ohm meter has a tone setting and though the switch would sound the tone, it reads around 30-40 ohms.
I plugged the switch into the car and pressed the ball: no lights.
Jumped the plug: lights.
I flushed it with contact cleaner several times but no change.
30-40 ohms is way too high. At least on my '92 I calculated the backup lights need 7 amps. V=IR, which means at 7 amps and 30 ohms you would drop 210 volts, which obviously is much more than the electrical system provides. I have the same problem as you and purchased a replacement switch with the pigtail, but have been working on a radio install and have not gotten to that yet.
30-40 ohms is way too high. At least on my '92 I calculated the backup lights need 7 amps. V=IR, which means at 7 amps and 30 ohms you would drop 210 volts, which obviously is much more than the electrical system provides. I have the same problem as you and purchased a replacement switch with the pigtail, but have been working on a radio install and have not gotten to that yet.
I feel stupid for not seeing this when I first tested the switch. I know better. It was tricky holding the test leads onto the contacts so I was just going by the sound.
I own a HVAC business and our techs always check resistance across switches and relays. They find many failing components during routine maintenance saving the customer the cost and inconvenience of an inevitable no heat/no cooling service call.
I feel stupid for not seeing this when I first tested the switch. I know better. It was tricky holding the test leads onto the contacts so I was just going by the sound.
I own a HVAC business and our techs always check resistance across switches and relays. They find many failing components during routine maintenance saving the customer the cost and inconvenience of an inevitable no heat/no cooling service call.
Ordered the switch from Corvette Central on Wednesday and received it in the mail today (Friday). Zero ohms with slight pressure on the ball. Installed on car and problem solved.
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Originally Posted by TimV SR
I have a '96 ZF-6 with no reverse lights. The trans was recently purchased used and came with a Hurst shifter already installed.
Everything works great, but I have no back-up lights. Jumpered the switch plug and the lights work. Pulled the switch and it makes contact with the ball depressed about 1/8"
I checked the plunger in the trans for movement in and out of reverse gear and it does not seem to move out enough to push the ball enough to close the switch. The switch is fully seated.
Is there an adjustment on the shifter linkage (or elsewhere) that will change this?
By the way, I found a great tool to remove the switch: a crowfoot style oxygen sensor socket. 7/8" socket extended just the right amount with an offset 3/8" drive square hole. Rented it from Autozone.
TTT and thanks
I got the slave cylinder out an was wondering how to get it out.
I decided for a solution that will make the switch easier and faster to replace.. at least for me.. but I didn't have carpet in the way.
I made a hole in the trans tunnel that allows using a deep socket from inside the car.
no special socke tneeded.
I will make a circle cover that is slightly bigger than the hole so it csn be easily removed to get a the switch if needed again.
I decided for a solution that will make the switch easier and faster to replace.. at least for me.. but I didn't have carpet in the way.
I made a hole in the trans tunnel that allows using a deep socket from inside the car.
no special socke tneeded.
I will make a circle cover that is slightly bigger than the hole so it csn be easily removed to get a the switch if needed again.
I would be displeased as the next owner with that modification.
hi chumpvette, I will have a tight fitting cover when finished.
it will be weathertight and tight fitting. plus covered by the sound deadening mat and carpet.
i understand my picture isn't showing it cleaned up and cover fitted.
love feedback of all kinds.. thats why this forum is great.
ZF-6 Back-up light switch adjustment?
