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1985 K5 Blazer Restoration Advice

dyeager535 said:
There are grounds everywhere. Underdash (bus bar driers side, behind the dash above the kick panel), back of engine to firewall, battery to probably both frame and core support, each headlight, each taillight, fuel tank to frame, any EFI stuff is likely grounded to the engine, and probably a couple more I'm forgetting.

I don't know as our gauges have pins, but procedure should be the same: https://www.corvetteforum.com/forum...179-water-temp-gauge-test.html#post1556373364

Senders and gauges are quite robust. The grounds in the truck, and the flex circuit/IP connecter on the back of the gauge cluster, are not.

Senders can be tested with an ohmmeter as long as the ambient/sender temperature is known. But you have to know the expected resistance values of the sender at that temperature. That info is out there, but too much work for an unlikely problem IMO. Both gauges acting the same way doesn't lead me to believe it's two senders coincidentally failing at the same time.

Likelihood of problems, in order IMO are ground(s), IP connector/Flex circuit, wiring, senders, gauges.

Could be wrong, but with the other lighting issues, ground problems are at the top of the list.
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I really appreciate the run down ill definitely keep it in mind when I work on it this week. Ill start with the grounds and hopefully ill find the issue. The flex circuit seems to be in good condition I cleaned it up, inspected it and nothing seemed to be broken or even peeling. I cleaned all of the connection points on it as well.

I guess ill start diggin and applying some elbow grease to these grounds, then i'll report back.
 
Cleaned all of grounds in the engine bay and the six spade ground under the dash. After testing, it fixed all of the dash lights being on when using the right blinker, but it still stalled and stayed lit when the headlights were on. I replaced the flasher relays when i noticed the hazards weren't working too and that fixed all of my issues. The turn signals and headlights all work as they should now.

But fixing the grounds didn't fix my temp and pressure gauges, I look at all the wires and everything looked fine nothing was exposed that could be grounding out the gauges. But for both to be out it does seem like there has to be a ground somewhere I missed or its another issue.
 
Do they respond properly with the "test" I linked prior? You can always check resistance to ground through the sending units, should be some resistance, not infinite, not none. That's a bit arbitrary, but if it is the senders that are bad, it should be pretty obvious by the numbers.

The senders vary resistance to ground via temperature or pressure for those respective gauges. Hot or cold will show different resistance if you are using an ohmmeter to test. But again, this is somewhat arbitrary. If the sender was truly the cause, then if the gauges are maxed one way or the other all the time, then hot or cold, the resistance reading will not change. Being pegged out one way or the other, a check with the ohmmeter should show infinite or no resistance. Not a value between those. IIRC the temp/oil pressure/fuel gauges operate between 0-90 ohms.

It's been awhile since I've had to deal with malfunctioning gauge circuitry, but I seem to recall that the gauges generally "float" a bit once the ignition is turned off. Once the circuits get power (key on), the needle will immediately peg for especially oil, since the pressure reading is obviously zero with the engine off.

If the senders are a pain to get to, you can always test resistance at the IP connector, as long as you know you have the right wires and you don't have to tear your dash apart to get to that point. That doesn't eliminate the wire between the IP connector and the sender, but it will help narrow it down.
 
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I ended up getting 90 percent of the wiring issues I had with this Blazer fixed up, minus the gauges after replacing all of the senders and replacing or repairing any damages in the wires in the engine bay. But then a big freeze came to Texas and a squirrel decided to destroy all of my work and then some, blowing the fusible link and more. It pulled about 20 wires of unknown origin that took me weeks to figure out because of all the grime on them and my colorblindness. IMG_6999.jpgIMG_7009.jpgIMG_7008.jpg
But I managed to get everything put back together and it worked great for about a month or two. But now it seems I have a parasitic draw, I used my ammeter and pulled each fuse one at a time but nothing lowered the draw. I unplugged the alternator, which maintains the battery at around 14.7-14.9 while the truck is running, and that lowered the draw to 10mA. I took it to the part store and they said it passed so im curious if anyone could help me out with how i should diagnose this and fix it. IMG_7571.jpgIMG_7575.jpgIMG_7574.jpg
I still need to fix the oil and temp gauges and from the troubleshooting I done and replacing the senders, I need to tear into the dash more when I get time away from school. But need to tackle this electrical drain first.
 
Before the electrical issues and after fixing the squirrels damage I had a slight tick coming from somewhere. I was 90 percent sure it was exhaust related but a few friends and family swore it was a lifter so i tore the engine apart and replaced them. As well as cleaned up and loomed the wiring in the engine bay, but when removing the manifold I had never noticed the TV cable was never attached to the throttle. (I believe it is a 700r4 trans)

Im no expert but had driven the truck several hundred miles since I purchased it and it always shifted good as it was. I adjusted the TV as best I could from my research online to limp it a few miles home and it only really shifted into second but i didn't get it over 35. I have test drove it once since and got it to 55 but it's impossible to tell when it shifts with how rough the roads in Dallas are and how rough this truck rides. I haven't driven it since because I don't want to burn up the transmission.

What is the best way to go about this? I have researched on CK5 and saw a write up Wes Harden had done which really helped me understand the function of the TV cable more. Should I follow that and see how it does? Or is it worth the extra effort to drop the pan to adjust the cable? There seems to be alot of differing views on TV cable adjustment online which has made me hesitant. IMG_7361.jpgIMG_7362.jpgIMG_7349.jpg
These are the only pictures I can find of how it was set up prior. From what i've read online im suprised I drove it as far as I had with it set up this way. but never thought anything about it as it drove home perfect the day i bought it and afterwards. I dont think I have the geometry bracket I think I will to properly set it up but am looking for advice on this as well.
 
The tick also turned out to be an exhaust leak like I had predicted and I realized it after replacing perfect looking lifters. But I probably wouldnt have noticed the Tv cable problem for alittle while had I not dug into the engine.
 
Tested the old alternator to see if a diode was messed up but it is functioning, also went ahead and installed a new alternator. But there is still a drain on the battery, electrical is my least favorite thing to tinker on. I'd assume this means theres something in the circuit causing the draw if its isolated to the alternator what are somethings I should look into to chase this down?
 
remove negative lead, place a test light between negative post and cable, if it lights there is a draw. If it's not lit open door it should light if dome lamp circuit is working.

If lamp is lit when door is closed, fuses need to be removed. 1st fuse to remove is the courtesy fuse, since door needs to be open so you can remove fuses. 2nd fuse to remove will be radio fuses, bat hot and keyed hot. then lights, power windows horn, all bat hot fuses. if test lamp is still lit pull the rest one at a time until test lamp goes out. If it doesn't go out after all the fuses have been pulled, remove the wire at the junction block/firewall bus bar, one at a time.
 
Wes Harden said:
remove negative lead, place a test light between negative post and cable, if it lights there is a draw. If it's not lit open door it should light if dome lamp circuit is working.

If lamp is lit when door is closed, fuses need to be removed. 1st fuse to remove is the courtesy fuse, since door needs to be open so you can remove fuses. 2nd fuse to remove will be radio fuses, bat hot and keyed hot. then lights, power windows horn, all bat hot fuses. if test lamp is still lit pull the rest one at a time until test lamp goes out. If it doesn't go out after all the fuses have been pulled, remove the wire at the junction block/firewall bus bar, one at a time.
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I followed this method using my multimeter but I will go ahead and have a buddy help me this time and use a test light. I didn't find anything initially pulling fuses but will try again and will try the junction in the engine bay didn't think of that. Thank you for the help.
 
Blue85 said:
If that image with the air cleaner on is the "before", it looks like they just bolted the end of the cable itself to the throttle lever and just didn't use the clip. That's OK, as long as the geometry is right. Sorry to hear about the bat ratsturd squirrel.

View attachment 500787
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From what i've looked at in past pictures it looks like the metal stop was just dangling, im not sure how they would've attached it without the clip. But I will definitely look into it more that could've been the case. Thanks for sharing this diagram, not sure exactly how im going to go about testing the geometry but i'll figure it out I think ill need to purchase one of the geometry kits.
 
I got the parasitic drain taken care of, it seems that when the fusible link blew on the fire wall the fusible link in line to the starter may have also blown. There wasn't a full break in the wire but definitely exposed, replaced with a new fusible link and its working great.

I should be getting in the geometry bracket today to fix up the tv cable and then I can focus on getting the interior put back together. I painted the interior trim a few weeks back an hope i can get the headliner finished to put it all back in, just need to decide what I want to do with the headliner.

Thanks for all of the advice and help im hoping I dont need to mess with electrical anytime soon.

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