1986 Corvette: Can anyone tell me which relay is bolted to the firewall right beside the heater hoses and should there be resistance between the blue and the black wire?

 

It sounds like you're talking about the Blower Relay

Black wire is ground, the Blue wire runs through the Blower Resistors to the Control Head. What is your problem?

 

Thanks, yes it is obviously the blower relay from your diagram. The problem I face is a conglomeration of several that have been psted in the past 24 hours by others. My cooling fan comes on whenever the ignition is on(constant trigger on green/white wire from ECM). The car is running very rich and may flood out at idle. I have noticed very low voltage on some grounds (intermittent). Tomorrow plan to check main ground and that of ECM. EGR is stuck open, so.......kiss the morning goodbye. Replaced the coolant temp switch and connector, plugs, wires, cap, rotor, ignition coil. Ignition module and pickup coil tested good. Continue to get a Code 42, occasionally a Code 14. Replaced fuel pump and relay. New timing chain and gears, water pump and harmonic balancer. Can hear strong hum coming through the stereo. My wife's cat is pregnant There is no room for upward mobility at my job because of the sluggish economy. My hair is thinning (falling out or pulling out: I'm not sure). Speaking of the wife, I think she is about to accuse me of an affair with the car, because I spend far more time with it lately than I do with her (OK, so these problems aren't all bad). I'd rather not explain what happened to my old manual, waiting on new one to arrive from Helm. This all being said, have you got any good advice/suggestions/secret ways out of the country? Any and all are greatly appreciated. Thanks for reading through my rant.

 

Check the A/C pressure switch to be sure it isn't stuck open; otherwise the ECM may be in limp home mode.

A scan tool would be a big help now.

 

Oddly enough, alot of this did start right after the ac was recharged in May. Didn't know there could be a connection (this is the type of thing that makes this forum invaluable). I check in the morning. Thanks.

 

The first thing that comes to mind is suicide, but if you think that emigrating is a viable solution, I can help you there. I left the US in 1984 and have been a tax exile ever since. Let me know if you're interested in this. ;) If fixing your car is still in the cards, Jim's suggestion about the A/C switch is a good possibility for the fan problem. To check this out, disconnect the A/C HIGH PRESSURE SWITCH in this drawing

it's a two pin connector with a black wire and a green wire. With it disconnected jump the two female pins of the loose connector (not the switch). With it jumped, your telling the ECM that pressure is OK and the fan doesn't need to run. Switch ignition on and see if fan still runs. I kinda suspect it will as I'm thinking ECM problem. Do this test first, and if the fan still runs, let me know. I can send you a spare ECM you can try, but I'd first pull your ECM, reseat the two connectors and also reseat the PROM and see where you are.

 

You said you measured zero volts at the CTS wire.
The ECM supplies the Yellow wire around 3-4 volts.
The Black wire is ground. So if you're reading zero volts with the ignition on,
across the connector plug (yellow and black) verify the yellow wire is not shorted to ground.

With the ignition off and plug disconnected, take an ohm meter and measure the resistance of the CTS sensor. At 70 degrees F the thermistor should read 3.4k ohms. At 100 degrees F the thermistor should read 1.8K ohms.

Error code 14 indicates something is wrong with the coolant temperature sensor circuit. (high temp. indicated) This could be why the fan is coming on.

Also are you clearing the codes by disconnecting the battery as you're trouble shooting so you're not looking at old codes?

 

Ray, thanks for the suggestion (LMAO)! Think I'll hang out in this old world a little longer - at least until I fix this @$&* car. I'm going out to check the switch right now. Hooked on Vettes, sensor tests good, yellow wire usually has 5 volts but ground has small amount of voltage. Sometimes both are at 0. This is why I wanted to check the major grounds. I am wondering about the status of the ECM at this point and plan to backtrace the wires for the cts and injectors before the day is out. Thanks for the input guys, and I'll let you know what I find.

 

Oh yeah, I am clearing the codes almost daily as the battery needs to be recharged from all the messing around with the car and this, of course, disconnects the battery and clears the codes. Thanks.

 

You must have better luck than me. I tried to get an 86 serivce manual from Helm and all I got was lied to a couple of times. Finally got my money back after 2 weeks of hassle.

 

hngacurv, I'm still in the waiting for it to arrive stage. It's only been a week and a half and it supposedly has to be printed for each order(?). Should I start checking on it now, or wait before I request the company line? I found an original 86 for half price, but thought there may be updates in a more current version. Maybe I should check back on that original.
Dan Quayle, check high pressure switch, jumped the connector and made no difference. Battery voltage on green, ground on black. ?? Rain delay on checking the grounds.

 

Ray, just how do you evade taxes in merry old England? I hear they are tougher to outfox than the IRS. :D

 

Since I left the US at the end of 1984, I've worked on Military contracts in three different countries, Seychelles, Greenland and since January of 1990, England. That allows you to fall under what is called the Status Of Forces Agreement. One of the benefits of SOFA is that you are exempt from foreign taxes. As far as US taxes go, if you qualify under the Physical Presence Test or the Bona fide Residence Test, you can qualify for the Foreign Earned Income Exclusion. This enables you to exclude up to a certian amount of your foreign earned income from US income taxes. When you earn a little as I do, the Exclusion covers all your income. :party:

 

Found a little problem with the main ground coming off of the battery. It was rubbing against the column/knuckle right below the brake booster. Half of the insulation for about an inch was gone, with green corrosion mixed in with the copper strands, so the battery was grounding to the steering shaft there. Applied some liquid electrical tape and click tied it out of the way for temporary fix and wouldn't you know, it starts right up, no smoke and the codes are disappearing. The Code 14 and 42 came back for a moment and then the next run ( without clearing codes) had no ses light. But now the radio doesn't work and the fuse is good. Big deal. Gotta go get some gas and I'll really check out my timiing etc. Let you know what screws up on that trip. Thanks for the help and you know - this is probably not over.