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Hello everyone my intermittent wiper function is broken on my 78. I have done what feels like lots of digging and so far have come up empty handed. I believe that my wiper delay control module is to blame but im not sure what's wrong with it. I've read lots of other threads about other circuit boards with blown capacitors / broken components on the circuit board itself that cause it to stop working. I have taken out my delay controller and thoroughly visually inspected it and everything seems to be in order, all electrical components seem to be intact and in good condition for being 45+ years old. Some of you will probably tell me to go and buy the $200+ replacement that's being sold on Corvette Central and whatnot and yeah I might do that but right now I'm on a tight budget. I want to feel accomplished for saving $200+ on an accessory and I think I can definitely fix whatever skybox era electronics is haunting me right now, I just don't quite know what I'm doing. One other thing, I'm really tempted to go and bench test this unit to try and get it to do something, make a click or anything but I'm also scared that i might fry this delicate breadboard and then have no choice but to buy a replacement. I also recently bought a replacement windshield wiper switch thinking that the resistor and whatnot inside the old stalk broke, causing the wipers to just come on as if they were set to low speed while in the delay setting. All but one other settings on the switch seem to work fine, the washer pump wasn't doing anything. I read that when you press it the pump is supposed to kick on via the delay module and then the wipers will go a couple times before parking. When I pressed down the button I noticed slight power loss as I watched my volt gauge drop a smidge. I disconnected the wires to the fluid motor and the voltage drop is gone so I think the motor is seized, found a replacement for $20 that I'm going to go for. any sort of information on how to safely test and diagnose my wiper delay unit is greatly appreciated! P.S yes I have checked my fuse box and such and there seems to be no blown fuses on the panel. But maybe there is something missing from the electrical? This car has been messed with somewhat but everything is mostly fine. Maybe there is a missing plug in piece that is preventing the delay to function properly? Not sure. (I did unplug my seatbelt buzzer but I don't think that's the problem)
Here are a couple pages from the 1978 Corvette Electrical Troubleshooting Manual, same manual the GM Technicians used back in the day...
First page is the line diagram second page is Circuit operation..
Read and understand the Circuit Operation...
Make sure you pull the inline fuse then check it...
I suggest you purchase the 78 Corvette Troubleshooting Manual.
You can find them on ebay...
A good used manual sells for around $25 - $40...
On your Circuit board you will see 2 Transistors I circled in RED.
Each should have a number on them, the number that is on them may be discontinued but the number should cross to a current good number...
For an example the Transistor I pulled from a Low Fuel Module number was 6681E.. I crossed that number and it crossed to a Sylvania ECG 159
1978 intermittent wiper delay broken + washer pump
my intermittent wiper function is broken on my 78. I have done what feels like lots of digging and so far have come up empty handed. I believe that my wiper delay control module is to blame but im not sure what's wrong with it. I've read lots of other threads about other circuit boards with blown capacitors / broken components on the circuit board itself that cause it to stop working. I have taken out my delay controller and thoroughly visually inspected it and everything seems to be in order, all electrical components seem to be intact and in good condition for being 45+ years old. Some of you will probably tell me to go and buy the $200+ replacement that's being sold on Corvette Central and whatnot and yeah I might do that but right now I'm on a tight budget. I want to feel accomplished for saving $200+ on an accessory 
and I think I can definitely fix whatever skybox era electronics is haunting me right now, I just don't quite know what I'm doing.
One other thing, I'm really tempted to go and bench test this unit to try and get it to do something, make a click or anything but I'm also scared that i might fry this delicate breadboard and then have no choice but to buy a replacement. I also recently bought a replacement windshield wiper switch thinking that the resistor and whatnot inside the old stalk broke, causing the wipers to just come on as if they were set to low speed while in the delay setting. All but one other settings on the switch seem to work fine, the washer pump wasn't doing anything. I read that when you press it the pump is supposed to kick on via the delay module and then the wipers will go a couple times before parking. When I pressed down the button I noticed slight power loss as I watched my volt gauge drop a smidge. I disconnected the wires to the fluid motor and the voltage drop is gone so I think the motor is seized, found a replacement for $20 that I'm going to go for. any sort of information on how to safely test and diagnose my wiper delay unit is greatly appreciated! P.S yes I have checked my fuse box and such and there seems to be no blown fuses on the panel. But maybe there is something missing from the electrical? This car has been messed with somewhat but everything is mostly fine. Maybe there is a missing plug in piece that is preventing the delay to function properly? Not sure. (I did unplug my seatbelt buzzer but I don't think that's the problem
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