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Topic: 1990 C4 Right Turn Indicator on Cluster is Dim

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1990 C4 Right Turn Indicator on Cluster is Dim (1/10)
1/27/14 12:51pm

Crouchley
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Pasadena, MD - USA

Vette(s):
69 big block & 90 L98 6 speed

Joined: 1/7/2014
Posts: 12

Last month I did the heater core, this month I am on to bigger and better things: The right turn signal indicator in the instruments cluster is about half brightness. Not a problem at night but cant see it in the day time. It is supposed to be a 161 bulb. These bulbs dont normally fail dim but it seems logical to be the first place to check it out. My factory manual is not clear on how to get to these bulbs. From the drawings it looks to me that the cluster is sunk into a "tub" meaning there is no access from behind. Is this true? Any suggestions? How about dropping the steeering column? The turn signals work fine by the way.

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (2/10)
1/27/14 2:26pm

CaledoniaBrian
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, - Canada

Vette(s):
1988 Convertable

Joined: 11/3/2011
Posts: 150

The 90 is a lot different than my 88 star-wars dash.

Last year when I lost the lighting on the left side of my cluster, I pulled the two offending bulbs out with a small piece of rubber hose. Saved taking the dash cluster right out and replacing bulbs after dismantling the cluster.

Might work for your turn light indicator also ??

______________

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (3/10)
1/28/14 8:40am

Crouchley
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Pasadena, MD - USA

Vette(s):
69 big block & 90 L98 6 speed

Joined: 1/7/2014
Posts: 12

I did some more research last night. I believe I am correct about the "tub". That is the cluster fits down into a tub. There is no acces from behind and yes the steering column must be droped but that doesnt seem like a big deal. I found a great thread on CAC where a guy acually repaired his LCD. Great writeup with pictures. I saw some information that changing the bulbs in the circuit board might not be as easy as it should be but it wasnt real clear. Still searching..........

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (4/10)
1/28/14 7:36pm

way2fastc4
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Plano, TX - USA

Vette(s):
1992, 6-spd, wht/wht, Keith Black Pistons, Perfect Circle Rings, Comp Cams Extreme-Energy Cam & Magnum Roller Rockers & Lifters, JBA SS Headers, Catco Cats, ARP, DeWitts Radiator, Pioneer-Polk Audio Sound, Torque Thrust II/Kuhno Ecsta MX, & more!

Joined: 8/21/2010
Posts: 3

Congratulations on just finished your heater core! After tackling that neck-cramping chore, I bet pulling the instrument cluster (& nearly anything else) will seem easy!

I agree; I can't imagine a bulb dimming (vs burning out), unless it has some corrosion built-up between the bulb & the bulb socket, which means you are still removing the I/P cluster anyway.

Here's how...

Remove the lower trim panel (open the door to get to the two screws on the side & there are two more on either side of the lamp area, & there's also a round retainer thingy that attaches the panel to the steering column, down by the pedals that you can usually unscrew from its stud).

Once you can drop the lower trim panel down, remove the ALDL connector bracket & 'carefully' unplug the foot-well lamp harness from the foot-well lamp housing (I learned the the hard way that those clear plastic tabs are very easy to break!).

Remove the drivers side metal knee bolster (open the door, there are two bolts on the side & two really close the transmission hump).

The shop manual says to pull the air bag fuse, but disconnecting the battery is a better idea when inside the dash.

Loosen the steering column bracket bolts to drop the column some & tilt the wheel down all the way.

Remove all the instrument panel lens screws (two at the top & two at the bottom).

Remove the instrument cluster screws (two at the bottom & two on the outer edge) & then pull it straight out (the cluster has a plug mounted on back that disconnects as soon as you pull it out).

There are 20 bulbs inside the cluster. Eventually, I plan on putting LED's in mine, so I only replaced the burnt ones.

Also, while the I/P is out, it is a good time to replace your blinker flasher, since it's located right behind it (get a solid-state type flasher, if you ever plan to update to LED tail lights in the future & I was told they last longer).

Good luck!

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (5/10)
1/29/14 12:56pm

Crouchley
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Pasadena, MD - USA

Vette(s):
69 big block & 90 L98 6 speed

Joined: 1/7/2014
Posts: 12

Thanks for the tips. I was heading down that path last weekend just short of dropping the column however I was still thinking I could get to the bulbs from the rear. Obvously not the case! However I have two questions. Is there enough slack in the cable that plugs into the I/P to follow the Panel as I pull it out, or in the other case, when it goes back together I will have to plug it in after the cluster is in place? Second question: Are the lamp recepticals hard to get out? I thought I read somewhere they might be glued in?

Thanks

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (6/10)
1/29/14 2:52pm

TLAVAC
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beaufort, SC - USA

Vette(s):
1990 Turquoise Corvette (his) & 1990 Turquoise Corvette (hers)indy festiville car for sale

Joined: 9/1/2009
Posts: 37

remove the trim around the cluster,the lower panel.remove the bolts holding the column,lower it carefully.remove the cluster.ck the connectors where the plug into the dash.clean them up and ck the grds.it usually is never the bulb.if you have the manuals,it will be an easy job as long as you have the time.

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (7/10)
1/29/14 4:18pm

The male & female plugs are fastened into each piece (like a card-edged type plugs on a computer board), so it all unplugs just from pulling it out & it all plugs back in as you push the cluster back in.

I was going to scan a page from my shop manual, but I found this website that has better pics of the backside & all the bulb locations... http://www.batee.com/corvette/dcrg/bulbs_9096/

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (8/10)
1/29/14 7:47pm

Crouchley
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Pasadena, MD - USA

Vette(s):
69 big block & 90 L98 6 speed

Joined: 1/7/2014
Posts: 12

Good link! I shouldnt have any problems. However the plug still sounds a little scary. Feeding that big cluster down to all those pin connectors seems awful ambitious to me. We will find out this Friday when I get home from traveling. I will report out then. How bad can 8 screws be?

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (9/10)
2/1/14 9:33am

robfogle
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Racine, WI - USA

Vette(s):
1984 C4 Black with Grey Interior

Joined: 10/30/2013
Posts: 1

Here is a link to the removal procedure that I found helpful....

http://www.corvettedashclusterservice.com/Ucandoprocess1.html

______________

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Re: 1990 C4 Right Turn Indicator on Cluster is Dim (10/10)
2/1/14 12:24pm

Crouchley
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Pasadena, MD - USA

Vette(s):
69 big block & 90 L98 6 speed

Joined: 1/7/2014
Posts: 12

JOB COMPLETE! Thanks for all the tips and guidance! OK, now time for the vote! Which was it:

1) Bad supply Voltage

2) Bad ground

3) Bad Bulb

4) Bad plug

5) Bad receptacle

6) Bad printed circuit board

The answer is 3: Bad Bulb

The bulb when powered looked like a flash light with low batteries. Very simple.

You guys are right-compared to the heater core this job doesnt even rate.

Here are a few things I can add:

According to the electrical schematic the indicator bulbes are feed right off of the turn signals i.e. if the signals are working then there should be power to the indicators.

The bulb (161) in the receptacles are one in the same ( it is even written on it). With a lot of trouble you can pull the old bulb out and put a new 161 in but it is extreamly difficult. I spent 30 min on cluster time and 2 hour on the bulbs. Go find the right part ahead of time! Also be real gentle droping the column, it is a little tricky getting it clear of the cluster bezel without doing damage. The concern I had with the main plug was not an issue. There are dowles in the cluster that align it as it goes in and then there are further alignment pins in the plug. Great job GM!

Thats about it (easy peasy lemon squezme). Oh by the way, folks need to remember that 1990 models have a completly differnt dash design than early designs.

Next project: turn signal switch in column ( I will post a new tread on this)

p.s. I had called a cluster rebuilder to get his thoughts on my problem, boy, what a smoke and mirrors routine that was! Avoid this path-the cluster is not that hard to work on.

v/r

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