Days wheel not working and it is missing a pin

It is likely a roll pin that attaches the shift clutch arms to the trans-axle. These pins do not usually remove easily. Look carefully at each arm assembly to find the one missing. Replace with a new pin.

Hope this helps?

I think this is how it should operate:
When the day skipper pin is pushed down on skipper-wheel....
... the day skipper pin pushes a lever away from trippers... so the trippers will not engage the lever ... and the day of watering is skipped.

Turn power OFF.
Take off plastic cover over the wiring terminals.
See if that is how it works, and look to see if something is missing.
Here is close up based on Intermatic image of 14-day skipper wheel, and you can see (what I assume) is the skipper pin pushing a lever.
http://waterheatertimer.org/images/Sprinkler-day-skipper.jpg

Attach close-up photo of your timer.
If you have digital camera, set to macro or tulip icon for close ups... otherwise phone cameras don't give clear view unless lighting is good.

Assuming the timer is defective... I am not certain of Intermatic's warranty policy... except they have 1 year full warranty, and could send just the timer mechanism so you do not have to replace the box... steps: take photo of wiring, disconnect wires, snap or screw new timer into existing box, reconnect wires, and then send defect back to Intermatic.com.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

remove streering wheel,underneath it should be a pin approx 1- 1.5 cm long if this is missing or bent. replace.you can put a nail in its place of the same length & thickness.grease it before putting wheel back.

You could have a worn out wheel bearing.
OR
The wheel bearing lock nut has come loose because the split pin is missing. this split pin prevents the lock nut from becoming loose.

I don't have a diagram, but if I understand what you're saying, there is a copper ring at the top of the steering column, visible before you install the steering wheel. The copper pin is connected to the horn button. The intent being that when you press the horn button, it completes the ground from the steering wheel through the horn button, through the pin, to the copper ring.
If this is correct, there should be no contact between the steering wheel and the copper ring other than the pin. Check to see if there may have been a spacer (washer, etc) below the steering wheel on the steering shaft that holds it just far enough away from the copper ring so that only the copper pin makes contact.

You have Intermatic sprinkler timer.
The silver pin inserts into the yellow dial at 12:00 midnight, and it rotates the skipper wheel.
Skipper wheel is necessary only if you want to skip certain days of the week, otherwise the timer cycle repeats each 24-hour period.
To skip a day, the skipper pin is pushed down for that day. Leave skipper pin up for days you want to water.
Open following links for more information:
http://waterheatertimer.org/Intermatic-trippers-and-parts.html#sprinkler
http://waterheatertimer.org/pdf/How-to-Set-and-Troubleshoot-Intermatic-sprinkler-timer.pdf

R88 series timers at Intermatic.
Click on model number to see manual:
http://www.intermatic.com/products/timers/mechanical%20time%20switches/sprinkler%20irrigation%20timers.aspx

Add a comment if you have different timer

At fixya, we're not supposed to copy-paste from manual, but manual says information clearly.
If timer has the day-skipper wheel located lower left of large yellow dial:
Not every timer has day-skipper wheel, in which case timer works same for each day.
TO SKIP DAYS: Turn black skipper wheel COUNTER-CLOCKWISE
until today's day is in front of "14" arrow. Press pins DOWN on days
of NO watering. The skipper wheel must have all pins UP for daily
watering.

Additional instructions:
1. TO SET FIRST ZONE: For watering, push gold pin into slot on yellow
dial at desired ON time. For each 12 minutes of additional watering
add one pin WITHOUT skipping a slot.
2. TO CHANGE ZONES: Leave one blank slot on yellow dial after ON
line (gold pin), and valve will automatically advance to next zone.
3. TO SET ADDITIONAL ZONES: Repeat steps 1 and 2. REMEMBER
to leave blank space between zones
4. TO SET TIME OF DAY: Turn yellow dial CLOCKWISE, until correct
line is at end of silver time pointer. Do NOT turn silver pointer.
5. TO SKIP DAYS: Turn black skipper wheel COUNTER-CLOCKWISE
until today's day is in front of "14" arrow. Press pins DOWN on days
of NO watering. The skipper wheel must have all pins UP for daily
watering.
6. PUT SELECTOR SWITCH IN AUTO: This switch can be used to turn
the system ON or OFF for manual operation without affecting the set
program.

http://waterheatertimer.org/Intermatic-trippers-and-parts.html#sprinkler
http://waterheatertimer.org/images/R8806P101C-timer-778.jpg

1) The silver pin goes at 12 midnight on large yellow dial. This pin advances the skipper wheel each day.
2) Turn yellow dial clockwise until current time lines up with silver pointer.
3) Rotate skipper wheel counter-clockwise until today's day (Monday) is in front of 14 arrow.
4) To skip a day of watering, the skipper pin is pushed down for that day. So you want to push down Monday and Tuesday.
For watering, the skipper pins is up for that day. So you want The skipper pin up for Tuesday.
5) The brass trippers are inserted on yellow wheel. Each brass tripper represents 12 minutes of watering for example. So if you want to water for 1/2 hour, then put two consecutive pins on the yellow timer wheel. For 1 hour, put 4 consecutive pins.

1) Traction drive belt slipping or worn
a) idler pulley not fully engaging
b) cable/lever adjustment
c) spring missing or broken

2) Friction drive disc slipping or worn
a) rust on hexagon shaft not allowing friction disc to move
b) missing or broken engagement spring

3) clevis pins missing or broken on wheels

4) roll pin on drive shaft missing or broken
inside the cover for the gearing mechanisms, chain drives, gears ect.

I’m happy to assist further over the phone at https://www.6ya.com/expert/rolandw_c013176d62ee17ae

I am RETURNING it to TARGET!