Author Topic: C4 1990 Third Brake Light (Read 20936 times)

Vettech · « **on:** September 28, 2019, 04:07:28 PM »

Now for the job I was trying to fix before the Airbag/seatbelt lights got in the way.

My hi level 3rd brake light does not work, because of the lack of staff at home, testing is a problem.
Suffice to say the globes (4) are all OK. In a C4, this cct comes directly off a seperate switch located on the brake pedal assembly.

Like other lever actuated switches - it is a semi floating arrangment, so you would say "Well just adjust it", unfortunately stuffing a 6' 11/2" person upside down head first under the LH dash is not easy, even though its had Left to Right hand conversion (chain&bar) the switches are still on the LH side right up under the dash, glove box and a miriad of other stuff which precludes the ability to see any thing.

After a "nasty glare" I've decided not to proceed any more today as "We" are going to a Corvette breaky run tomorrow....

If you have had this issue please let us know what you found.

Ausrs · « **Reply #1 on:** September 28, 2019, 06:22:36 PM »

Maybe change the halogens in the 3rd brake lights to led globes (got mine off of ebay) to lessen the load on the switch and simply wire the 3rd brake light into the existing functioning rear brake switch
via the back lights , means you do not have to stuff yourself under a dash

bfit · « **Reply #2 on:** September 28, 2019, 07:38:34 PM »

There’s a good thought, more than one way, as they say
Bfit

Vettech · « **Reply #3 on:** September 29, 2019, 04:12:57 PM »

Thanks gents - all good info.

As usual not straight forward.

I had D4 on the brake, after I moved a heap of bibs & bobs, I could see the switch and adjusted it, Nothing ..... umm.

Pull the third light off, the only bulb that I refitted had burnt legs and were effectively O/C.

A friend from the Central Coast Codgers had given me 4 used, but good bulbs, quick refit - all now good.

Done and dusted - but now I'll investigate those LED's for ron.

This does raise another question ! This pedal switch has a second switch which I think is for the TCC !?!!.
My FSM is for 87, and I've had a niggerling feeling that the Torque Converter is not Locking up - but this is for another story.

Ausrs · « **Reply #4 on:** September 30, 2019, 02:59:13 PM »

2 switches on the brake, one for lights and one for cruise control,cruise one has a vacuum hose attached to it
link for globes that fit in 3rd brake light,the original ones I bought I did have to drill out the fitting (mine is also a convertible) and remember they only go in one way

https://www.ebay.com.au/itm/183298041763

The halogens are available from Bunnings

As for tq converter,it should kick in at 50 mph and it is noticeable on my 87 what is your economy like when using the car ?

I has my chip reprogrammed years ago and changed it to 35 mph

Vettech · « **Reply #5 on:** September 30, 2019, 03:54:58 PM »

Well the reason for an 87 FSM is because thats in the garage, being worked on. This 90 is my daily driver, as I'm often left with no car.

But - when it ran, you could feel it go up, 1, 2, 3, 4, Lockup and the OD light came on, on the dash.
Only after temp was up, and over ~ 72kph, but it could lock in 3rd as well.

110Kph at ~1200 rpm - just ticking over. Great economy.

My 90 Sales brochures has a loverly colour glossy of the instruments all lit up with an "OD" light - just like the 87.
BUT! - nothing lites on the actual 90 dash, and from youtubes and mr "Batee" - I cannot see any such lite or cct.

I'm beginging to think the Sales Brochure is just a gimmick. I kinda like seeing that light, lets you know whats going on.
I suppose for some drivers, the less info the better.
But if nothing else, I'm really happy after fixing these couple of niggiling things, and importantly I've now repositioned ALDL Plug so I can get to it easily.

Sunday had a look at a nice 90, but it had no "Infl Rest" or "Red searbelt man" obvioulsy globes have been removed, most likely it has my problem I just fixed.
The issue for that owner now, you cant interogate the "SIR" computer since it flashes it's codes using the "INFL REST" light. Even though I have a OBD thingo reader, I have never been successful in using it.
Regards

Ausrs · « **Reply #6 on:** September 30, 2019, 04:05:05 PM »

I feel the lock up in my 87,has never had a light
As for removing things,I removed the complete vats system from my 87 and the complete egr system from the memcal plus the lock up and temp that the fans come on at to make things a lot less complicated
I would suggest 1200 rpm at 110kph your converter is locked,If your cruise works find a slightly undulating country road and set cruise at 100,with mine you can actually feel the converter locking and unlocking
I have an old "auto xray" scanner that I have had for many years,it works,maybe one day you can try it..although I am in Newcastle

Vettech · « **Reply #7 on:** September 30, 2019, 08:39:59 PM »

Ummm. My 87 has every thing, all working, fans have additional thermostat, thats been put up on the LH side tophose to rad, adjustable.
I have on occassion tweeked it.

Currently working to fix heater matrix, oil cooler, piping. Hole in caseing for water needs re-threading. Etc etc etc

I have new A/C Accumulator, bought one to suit an early Commadore, (looks identical) has reversed fittings, makes for easy, neater re-piping. Once water done I can re-gas the A/C with the new gas I just used on the 90, Hi-Chill -30, works a treat.

And my wife says I do nothing at home........

Ausrs · « **Reply #8 on:** September 30, 2019, 08:49:28 PM »

Always something to do on these cars
list of replacement parts over 7 years with this car has been an expensive journey but on the plus side it has been all over Tassie and all over Victoria and I drove it up from Melbourne to Tumut and when I moved back from the northern rivers of NSW I drove it 7 hours straight down to Raymond Terrace
I do keep things like relays and icm,s in the car whenever I travel though
I hated replacing the brake booster,it was the sh#ttiest job I have had to do so far
Need to find some local vettes !

Vettech · « **Reply #9 on:** October 03, 2019, 03:59:41 PM »

Yes - you are right about that.

Just when I was feeiling great after fixing a few issues and getting new tyres, went out to put the kick panels etc back in place.

And the RH power window is not working, not a squeak, rattle or click of a relay.

My book is for 87, where the switches are on the centre console, LH side is Ok.

Ausrs · « **Reply #10 on:** October 03, 2019, 06:46:52 PM »

can you take the switch from the lh side and try it on the right? I am guessing you have dislodged a wire due to the rhd conversion though ...digging under a dash of a converted car is like playing with a nest of spiders

peterw · « **Reply #11 on:** February 15, 2020, 01:19:30 PM »

My third brake light had a few melted sockets so i got a small strip LED from the electrical store and wired it in clamped to a bit of cardboard and it works brilliantly.

This doesn't fix your problem but I thought I would put it up in case it helps someone.

Pete

Vettech · « **Reply #12 on:** February 15, 2020, 05:29:03 PM »

Pete.
So that is a strip of leds, tied to some card, and "set behind the front red lense, but in front of the reflectors".

Mine are again playing up, I did note before a lot of waterish looking dust inside - causing corrosion no doubt.

A trip to Jaycar may be in order.

peterw · « **Reply #13 on:** February 16, 2020, 12:45:25 AM »

My original bulbs melted the fittings, obviously someone sat in traffic with their foot on the brake for a long time. Those halogen bulbs must get hot.

The LED strips are cheap, they are 12v and brighter than the originals.

I bought them at an electrical wholesaler and they just cut them to length and put the pigtails on. They are marked with little scissors on the cut points so you can cut them to length yourself and they still work like magic..

Just tied it to some stiff cardboard. LED's don't generate heat so no problem there.

Soldered them to the point where the originals got their power and Bob's your uncle.

Pete

Vettech · « **Reply #14 on:** February 16, 2020, 10:11:32 AM »

Umm very good.

I suppose the proof is in the pudding.

As long as they illuminate the red lens and are Bright.

Maybe I will see at a club run. (Those original bulbs I think are 5 watts each - pretty hot.)

Regards.

peterw · « **Reply #15 on:** February 16, 2020, 11:51:15 AM »

Those COB LED's are very bright.

peterw · « **Reply #16 on:** February 16, 2021, 12:17:09 AM »

I finally remembered to take a photo of the LED's in action

Vettech · « **Reply #17 on:** February 16, 2021, 11:32:52 AM »

Well that looks very good.

I've seen similar at Jaycars et al, in fact I bought a set of Blue Leds years ago, and was going to put them on the blue car - but looked to much like a boy racer's car.

The lamp fittings etc are RS, the gasket seal is in pieces (unavailable) so it needs some work applied, including a Silastic home made gasket, its just getting the time - esp since I'm now at war with the RTA on Hplate issueing and paperwork.

I'm glad you put that pic up, they fill the bill and as you say the globes (×4) at 5W ea dissipate 20W which is a fair current draw at 12vdc.
BUT! being Mr Pedantic, the thing I dont like about LEDs is seeing the individual leds - it needs to be a bright homogeneous red plasma like light.
I built an electronic spirit level (Silicon Chip) with a red diffuser - um now where is it ?

peterw · « **Reply #18 on:** February 16, 2021, 12:41:02 PM »

I know what you mean about the individual LED's, I don't like them on modern tail lights either.

This light used to be 4 individual spots rather than a homogenous red bar. I can live with 15 spots.

Vettech · « **Reply #19 on:** March 18, 2021, 02:39:30 PM »

Yesterday fedup I finally bit the bullit and pulled the brake light assy off, no sooner had I done this , it bucketed down, the 90 now has a fine selection of 60mph tape plastering up holes in the rear hatch.

Removed, stripped down, cleaned, the globes are all ok, the sockets are intermittent corroded along with the cct hoard solder joints.

Now it's fully apart on the bench, I'll search some suitable leds, a trip to Jaycar is needed. As soon as I squeeze down some pics I'll put them up.

PeterW - I note no gasket on either of your pics, what did you use, the original is like a foam rubber and unavailable.